I made a short benchmarking comparison between ExFAT and NTFS in pure MBR and GPT modes.
<tl;dr>
NTFS is twice as fast for writing performance compared to exFAT!
And you shouldn't use the tablet's internal function to erase/format the SD Card.
</tl;dr>
SDCard:
Kingston SDCA3/64GB microSDHC/SDXC
- UHS-I U3, nominal speed: 90 MB/s read; 80 MB/s write
- According to some comparisons I found this card is currently one of the best with practical speeds nearly the same as the nominal speeds. (http://www.techfunology.com/electro...for-photography-action-cams-and-videocameras/)
Tablet:
Nvidia SHIELD Tablet
- classic non-K1
- 32GB LTE
- ROM: currently latest Lollipop stock 3.1.1
Benchmark:
A1 SD Bench
- https://play.google.com/store/apps/details?id=com.a1dev.sdbench
- Mode: Accurate - with reboot
-> reboot between write and read - a short test shows that the "Longer" mode with 5GB data results in similar values
results:
card erased by SHIELD itself
-> Settings -> Storage -> erase SD Card
-> results in exFAT MBR + GPT (but in a weird dual non-hybrid way, so you really shouldn't use the tablet for this!)
read: 80,97 MB/s
write: 18,91 MB/s
external formattings:
exFAT GPT (protective MBR)
read: 79,54 MB/s
write: 23,12 MB/s
NTFS MBR (no GPT)
read: 79,81 MB/s
write: 40,69 MB/s
NTFS GPT (protective MBR)
two runs:
read: 79,92 MB/s
write 40,44 MB/S
------
read: 80,27 MB/s
write 45,15 MB/s
As you can see, there is no real difference between MBR and GPT.
However, there is a huge difference between ExFAT and NTFS in writing speed.
NTFS is twice as fast for writing performance compared to ExFAT.
Reading speeds seem nearly the same.
The tablet's internal function to erase/format the SD Card should not be used as it produces strange formatting results.
Nice comparisons.
Just curious, which ROM version was this tested on?
Good point. It's on latest Lollipop stock v. 3.1.1
Would be interesting to see how this compares on MM 4.0 in either portable or internal storage modes.
I'm not really sure how one could test the infernal storage mode reliably. As far as I know it shows up as one large logical partition, so I don't see how it might be possible to just test the physical sd card of this partition. Has anyone more information about this?
Vankog said:
I'm not really sure how one could test the infernal storage mode reliably. As far as I know it shows up as one large logical partition, so I don't see how it might be possible to just test the physical sd card of this partition. Has anyone more information about this?
Click to expand...
Click to collapse
No, under settings --> storage you have to move apps to the SD card. Though I"m not sure how it works in a file manager app.
What did you use for the "external formattings"? I.e., what program?
I didn't try ntfs, exfat & adopted only:
https://drive.google.com/folderview?id=0B9k8W8e2YrFfQ1VCTlpfLUVualU
I think that k1 has sd card slot with max ~80/40 R/W.
Hi,
I don't think this story is still true on a new device with an newer Android. I also did a small benchmarking comparison between NTFS and exFAT.
SDCard:
Lexar Professional 1800x microSDXC 64GB UHS-II
- UHS-II upt to 270 MB/s read and 250 MB/s write
Tablet:
Nvidia SHIELD Tablet K1
- new K1
- 16GB
- ROM: currently Marshmallow 6.0.1 stock 1.5 (24.3.70.8)
Benchmark:
A1 SD Bench (https://play.google.com/store/apps/details?id=com.a1dev.sdbench)
results:
NTFS
read: 60.96 MB/s
write: 74.53 MB/s
exFAT
read: 82.64 MB/s
write: 71.32 MB/s
Best Regards,
Datafreak
Thanks for the new data, datafreak! :laugh:
Well, could be either the K1, the new OS version or a combination of both. But the 70 MB/s write speed is amazing.
Maybe I'll do a new test when I update to the latest version on my non-K1.
apollyon0810 said:
What did you use for the "external formattings"? I.e., what program?
Click to expand...
Click to collapse
Hm, I think it were several different.
On Mac the integrated one I think it is called diskpart, for Windows the integrated formatting tool should do the trick. Besides that I used a partition manager. I think it was the free MiniTool Partition Wizard.
dzidexx said:
I didn't try ntfs, exfat & adopted only:
https://drive.google.com/folderview?id=0B9k8W8e2YrFfQ1VCTlpfLUVualU
I think that k1 has sd card slot with max ~80/40 R/W.
Click to expand...
Click to collapse
What I/O scheduler did you use? noop,cfq,deadline? did you tune the i/o's or leave them stock?
m0nt3s said:
What I/O scheduler did you use? noop,cfq,deadline? did you tune the i/o's or leave them stock?
Click to expand...
Click to collapse
It was all stock(1.4), few days after I bought k1 - noop.
datafreak said:
Hi,
I don't think this story is still true on a new device with an newer Android.
Click to expand...
Click to collapse
Could also just be the different SD card, I'd say.
I have a Shield K1 with Android 6.0 and just ran A1 SD benchmark. Same memory card formatted to exFAT and then to NTFS (used windows to format each time). Almost the same exact read/write results both times. I am testing another card tonight when I get home, but I suspect it will be the same.
@seh6183
That's an interesting fact.
What are the speeds?
Vankog said:
@seh6183
That's an interesting fact.
What are the speeds?
Click to expand...
Click to collapse
NTFS
Read: 19.55MB/s
Write: 12.03MB/s
exFAT
Read: 19.72MB/s
Write: 12.21MB/s
I tested a much faster, much bigger card later that evening on both exFAT and NTFS and got the same results.
Related
Hello XDA forums,
Recently I installed Urukdroid 1.0RC2 on an A43 8GB model, and I noticed how my device only has up to 7GB of space. I was just wondering where the other 1GB is because I don't want to have wasted space sitting around doing nothing.
Thanks for your time.
This "problem" isnt a problem
its always the same: if they write 8 gb, there is formatted only 7-7.3 gb
look at your hdd on your computer
Hello and thanks for the quick reply.
Actually I do understand the deal with the 1024mb = 1gb, but are you sure that it is supposed to read 6.95 gb (that is what it says in Linux when connected)? I'm pretty sure it should more or less be around 7.4-7.7.
Sent from my A43 using XDA Premium App
Okey thats pretty much
hm.. than its because urukdroid's formatting
what did you select in urukdroid installation progress?
EDIT: You said thanks, psst... push the "Thanks"-Button don't hurt
@denwaotoko:
What do you think where the system itself is hostet?
Right it is on that 8GB internal memory.
It has 3 Partitions ( without Uruk ) which are for System, Data and Rest.
@fzelle correct.
as far as I know, the kernel splits the 8GB in two "virtual" devices which of one is 512 MB large and the other one 7,5 GB.
The first virtual device is /dev/block/mmcblk0 which contains rawfs (boot), swap, system and /data partition while the second (big!) virtual device is /dev/block/mmcblk1 and contains only one fat32 partition (internal storage)
so you only get 7,5 GB which in the end is about 7,x GiB formatted storage that can be used (don't have my A101IT with me so I can't give exact numbers)
chulri said:
@fzelle correct.
as far as I know, the kernel splits the 8GB in two "virtual" devices which of one is 512 MB large and the other one 7,5 GB.
Click to expand...
Click to collapse
Yes I do realize that, so is the 1gb of "lost" space just hidden?
denwaotoko said:
Yes I do realize that, so is the 1gb of "lost" space just hidden?
Click to expand...
Click to collapse
Jap, exactly
We can be proud of the fact that android uses only little memory space,
Windows for example use 20 gb
Alright, I was just expecting that it would show up in a partition manager when connected to a Computer.
denwaotoko said:
Alright, I was just expecting that it would show up in a partition manager when connected to a Computer.
Click to expand...
Click to collapse
Nope,apparently not
Thank you for thanks
denwaotoko said:
Alright, I was just expecting that it would show up in a partition manager when connected to a Computer.
Click to expand...
Click to collapse
No, it doesn't because the device only shows /dev/block/mmcblk1 and mmcblk2 to the computer, where 1 is the internal flash (the last 7,5G of the internal mmc as I explained before) and 2 is the external microsd.
I bought 64 gb card and it works on samsung stock galaxy s3 rom BUT when i switched to Cyanogen10 mod it started showing damaged card,
I know it is because the stock has driver for that card,
My question is has someone ported or can someone please port the driver from stock and make it workable on custom roms.
Thanks.
exFAT is not and probably will never be supported by CM9 or 10.
Your card needs to be FAT32-formatted to work.
Alright trying hopefully this works and doesnt screw up my card.
d4fseeker said:
exFAT is not and probably will never be supported by CM9 or 10.
Your card needs to be FAT32-formatted to work.
Click to expand...
Click to collapse
didnt work now the phone doesnt even show damaged card, its acting like card is not even inserted.
How exactly have you formatted the card? Windows onboard utilities won't let you format a 64GB card as FAT32, so my guess is you formatted it as NTFS.
Unfortunately CM cannot read NTFS either, you'll need another kernel for that. (And to date none has been released)
Try the HP Usb Format utility to create a FAT32 partition.
d4fseeker said:
exFAT is not and probably will never be supported by CM9 or 10.
Your card needs to be FAT32-formatted to work.
Click to expand...
Click to collapse
Why is this?! Does AOSP not come with exFAT support, it's something Samsung builds into the kernel afterwards?
Disappointed, as I was tempted to try CM, but no 64GB support renders my card next to useless.
Disappointed, as I was tempted to try CM, but no 64GB support renders my card next to useless.
Click to expand...
Click to collapse
FAT32 doesn't mean the card is restricted to 32GB, it means a file can be 2^32 bytes long which is 4GB.
FAT64 (ExFat) has a limit of 2^64 bytes per file which equals 16 Exabyte (1Exabyte = 1024 Terabyte)
It's possible for FAT32 partitions to be as large as 8 Terabyte, which is roughly 1000 times the size of harddisks when FAT32 was released.
Windows, for some stupid compatibility reason with a 12 year old operating system (Windows 2000) does not allow to format FAT32 partitions to a size larger than 32GB, hence the usual confusion.
As described above, here is the tool you need: http://www.softpedia.com/get/System/Hard-Disk-Utils/HP-USB-Disk-Storage-Format-Tool.shtml
Why is this?! Does AOSP not come with exFAT support, it's something Samsung builds into the kernel afterwards?
Click to expand...
Click to collapse
ExFat is patent-encumbered, meaning every distributed binary copy of Cyanogenmod would theoretically cost the developers the license fee.
(At least for US-based downloads, most other countries see software patents as what they are - ridiculous and unenforceable)
Furthermore -and a very big issue- is the instability of the exFat code for GNU/Linux (and by extension, Android) which causes data loss, corruption and other negative side effects.
It's highly recommended not to use exFAT with Samsung-firmwares either.
d4fseeker said:
How exactly have you formatted the card? Windows onboard utilities won't let you format a 64GB card as FAT32, so my guess is you formatted it as NTFS.
Unfortunately CM cannot read NTFS either, you'll need another kernel for that. (And to date none has been released)
Try the HP Usb Format utility to create a FAT32 partition.
Click to expand...
Click to collapse
i used easeus partition: i deleted partition first and made new one with fat32 file system,
which didnt work, after that i deleted the partition again and formatted using stock galaxy s3 rom and it works again but limited to stock rom only like before.
atleast the card isnt dead.
d4fseeker said:
How exactly have you formatted the card? Windows onboard utilities won't let you format a 64GB card as FAT32, so my guess is you formatted it as NTFS.
Unfortunately CM cannot read NTFS either, you'll need another kernel for that. (And to date none has been released)
Try the HP Usb Format utility to create a FAT32 partition.
Click to expand...
Click to collapse
ill try this software as well.
d4fseeker said:
How exactly have you formatted the card? Windows onboard utilities won't let you format a 64GB card as FAT32, so my guess is you formatted it as NTFS.
Unfortunately CM cannot read NTFS either, you'll need another kernel for that. (And to date none has been released)
Try the HP Usb Format utility to create a FAT32 partition.
Click to expand...
Click to collapse
I didnt get a chance to try Hp software i cant across this other software and it work.
Thank you though
d4fseeker said:
FAT32 doesn't mean the card is restricted to 32GB, it means a file can be 2^32 bytes long which is 4GB.
FAT64 (ExFat) has a limit of 2^64 bytes per file which equals 16 Exabyte (1Exabyte = 1024 Terabyte)
It's possible for FAT32 partitions to be as large as 8 Terabyte, which is roughly 1000 times the size of harddisks when FAT32 was released.
Windows, for some stupid compatibility reason with a 12 year old operating system (Windows 2000) does not allow to format FAT32 partitions to a size larger than 32GB, hence the usual confusion.
As described above, here is the tool you need: http://www.softpedia.com/get/System/Hard-Disk-Utils/HP-USB-Disk-Storage-Format-Tool.shtml
Click to expand...
Click to collapse
Thanks, though I realised this - the whole reason I need a 64GB card is to copy movies onto there, because I travel a lot... many of them are over 4GB, which is the issue I have with using FAT32.
d4fseeker said:
ExFat is patent-encumbered, meaning every distributed binary copy of Cyanogenmod would theoretically cost the developers the license fee.
(At least for US-based downloads, most other countries see software patents as what they are - ridiculous and unenforceable)
Furthermore -and a very big issue- is the instability of the exFat code for GNU/Linux (and by extension, Android) which causes data loss, corruption and other negative side effects.
It's highly recommended not to use exFAT with Samsung-firmwares either.
Click to expand...
Click to collapse
Maybe I should look at ext3 instead, though then I'd have problems putting it straight into my Windows machine. Though, exFAT has been 100% stable for me so far.
many of them are over 4GB
Click to expand...
Click to collapse
Ok that is a problem for FAT32. You didn't mention it so I assumed you mistook the 32 in FAT32 for 32GB as many people do.
Maybe I should look at ext3 instead
Click to expand...
Click to collapse
Since you should never need to remove or directly access the card (MTP mode or File transfer through 'Samba Fileshare' App) that should be a solution. For your own computers, you could use the following driver:
http://www.fs-driver.org/
It allows read-write access to EXT2. EXT2 being EXT3 without journaling support (and thus fully backwards compatile) that could do the trick.
Pententially you'll need to re-enable the journal again through tune2fs on the Smartphone after having used an EXT2-driver. Not sure though since the journal is only relevant until a clean dismount is made.
You should however also be able to load the NTFS-module in the kernel or recompile the CM10 kernel with the required options.
If you need to plug the SDcard into your computer a lot, that may be the only solution until Gokhanmoral is back.
I dont know if there is already info on this subject, but i recently got a sandisk 64G mSD and it didnt even seem to last a year - kept getting into 'read-only' mode for some reason..... i though it was my KKDS_1.4 (4.4.4) rom, link2sd and all the other stuff there, but dont know if that's the case kept having to do the following to get it out of read only mode :
Plug SD into windows and :
Start > Run > cmd
type "diskpart" -> runs diskpart.exe from system folder
type "list volume" -> now you see all your connected drives, see which one is the drive
type "select volume #" -> # being the letter of your drive
type "attributes disk clear readonly" -> removing the protection
Then open your SD, you can now edit, delete, move files.
However this didn't seem to last long... and think the SDcard on its last leg - even though i didn't use it much.... i did have a ton of pictures, videos, programs and music on it but still had about 12G free but was really slow - even though its one of the SanDisk Ultra 64G XC I (UHS Class 1).... Granted I do use Link2SD and have partitioned the card as follows [59G Fat, 4G ext4, 1G Swap], but cant account for things taking so long, and then sometimes finding the card in read-only mode.
Anyhow... from my reading i dont think android will even use the 'swap' space i made, so on future SD I plan on a 4G ext4 (for second partition) with the remaining 60G as a FAT32, ExFat, or NTFS - for my KitKat (4.4.4) Device - will one filesystem be better an any other for the first partition (windows / linux compatible) - im thinking NTFS (reliable & windows compatible) but not sure if KK supports write mode to NTFS filesystem? There is also ExFat - but not sure about android support for that either... Know many people suggest raw FAT but just not possible with todays bigger cards so kinda seem stuck with FAT32.
Regressing and getting to the heart of my post here, I was wondering if there has been any long term studies of Which mSD Cards last longer and transfer data pretty fast? Perhaps there are ones more reliable... thought Sandisk was pretty good (my USB 3.0 SanDisk Extreme 64 GB Flash Drive kicks butt) I know the technology is different but the 64G Ultra SDXC was UHS Class 1. (so at least class 10)... but its only a year old and already giving me trouble... what are the better cards out there -- and what filesystem should the first partition be set to to make it last (and usable in a windows [or linux] environment) ?
I did read over a few good posts :
http://forum.xda-developers.com/showthread.php?t=1544156
and http://forum.xda-developers.com/showthread.php?t=1150369
as well as a few other places here , here , here , and here
Im starting to think that since im using Link2SD perhaps class 10 card not optimal for the ext4 r/w , but i do use the primary partition quite a bit (like a flash drive ans dont want to wait eons while transferring all my tunes and videos etc to phone.....
Has anyone done any research into these issues? Are there any cards the use SLC nand? or just last longer?
Can anyone comment on any of this.
steve_77 said:
Anyhow... from my reading i dont think android will even use the 'swap' space i made, so on future SD I plan on a 4G ext4 (for second partition) with the remaining 60G as a FAT32, ExFat, or NTFS - for my KitKat (4.4.4) Device - will one filesystem be better an any other for the first partition (windows / linux compatible) - im thinking NTFS (reliable & windows compatible) but not sure if KK supports write mode to NTFS filesystem? There is also ExFat - but not sure about android support for that either... Know many people suggest raw FAT but just not possible with todays bigger cards so kinda seem stuck with FAT32.
Click to expand...
Click to collapse
I just answered on the other thread, but I wanted to add that AFAIK Android doesn't support NTFS (at least not without serious jigging) and I think exFAT is close to the same situation. Why? These are proprietary Microsoft formats (arguably FAT32 is as well, but it is based on the standard FAT16 and has been opened up considerably) that even for a Linux system have to go through hoops to get the drive to properly write (well, not too bad, install the ntfs-3g package).
I know using a thread it not necessarily the best way to ask a question but since the cause of this issue is unknown (and might just be SD corruption) and there are a few other threads where it might come up, this thread can be used as a reference.
The issue is: An SD card that rather suddenly became unwritable in every way and can no longer be mounted by Android (although it is detected) but on which all existing data was undamaged, can be viewed and copied via USB card reader to Windows or Linux PC. The drive behaves much as if it was write protected or as if the file system (particularly the FAT) was corrupted in a way that mimics digital SD write protection. Here are the details.
L5.1.1/CM12.1 December 2015, SuperSU 2.65, TWRP3.0.2,
- 64GB Sandisk Ultra SD, initially accepted as formatted or formatted upon first use to Fat32; Working fine for a few months as repository for static data (ROM zips and app apks), work material (frequently edited text, DOCX and XLSX files), as well as apps and app data with a dynamic presence on the drive.
- Drive suddenly stopped appearing on device in CM and in TWRP. When re-inserted in CM, the system detects a card but times out as it is unable to find a mount point. Attempts to mount SD card in ROM result in the following error in CatLog:
"E/Vold (222): /dev/block/vold/179:65 failed to mount via VFAT (No such device or address)
E/Vold (222): Volume sdcard1 found no suitable devices for mounting "
- Attempts to repair, partition or format the drive in TWRP result in mount error and the details of the drive have zeros where there should probably be other values.
/external_sd | | Size: 0MB Used: 0MB Free: 0MB Backup Size: 0MB
Flags: Can_Be_Mounted Can_Be_Wiped Wipe_Available_in_GUI Removable Is_Storage
Primary_Block_Device: /dev/block/mmcblk1p1
Alternate_Block_Device: /dev/block/mmcblk1
Display_Name: MicroSD Card
Storage_Name: MicroSD Card
Backup_Path: /external_sd
Backup_Name: external_sd
Backup_Display_Name: MicroSD Card
Storage_Path: /external_sd
Current_File_System: auto
Fstab_File_System: auto
Backup_Method: files
MTP_Storage_ID: 65537
- With SD in card reader attached to PC, the contents of SD are visible and can be copied to PC but files cannot be copied from PC to SD card. It looks like they are copied but they are gone when card reader is disconnected then reconnected. Same in Linux Ubuntu 14.x.
- Unable to delete or reformat partitions in any utility that I tested including: Dedicated GParted boot USB, EaseUS Partition Master, HP USB Disk Storage Format Tool on PC, GParted in Ubuntu 14 VM, GParted in Ubuntu 10.x live CD/USB.
- Although the SD drive shows as Fat32 in GParted, Windows 7 only offers exFat and NTFS as formatting options. Some research shows exFat can digitally "write protect" drives with a dirty bit or byte which causes very similar symptoms.
- Windows Chkdsk requests to convert lost chains to files but must not be doing so as this occurs on every scan.
Soooo...the questions are: What in the realm of relatively normal android use might cause this? Has anyone heard of a disk or partition management setting or common form of drive corruption that could cause this? Could such a thing be caused by a file manager? A 32GB replacement SD is doing OK but I'm left wondering if the issue with the 64GB SD card was caused by a utility on the device or if it was just SD corruption (that looks conspicuously like digital write protection).
[EDIT] A minor correction I should make: The reason Windows 7 only offers NTFS and exFAT is not because the drive is damaged (although it may be) but rather because Windows 7 cannot format USB drives over 32GB with FAT32 although it can mount and use larger FAT32 SD drives that were formatted elsewhere. In this case I let android do the initial format months ago (Fat32) and never had problems during the times I connected it to card reader (although I usually leave it in the device and use Wifi or MTP through device USB to PC).
[] AL [] said:
Since your running 12.1, I imagine that you don't flash too many nightly build's... So this (not) variable is may be put aside from suspects list.
Click to expand...
Click to collapse
Correctamundo
[] AL [] said:
Recovery: well, I don't know but for that, I'm always following the if it ain't broke, don't fix it rule. You have specific reasons to keep it updated? Like you, I've also read many posts reporting USB related issues with v > 3.0. I still use v2.8.7.0 on my device and don't feel the need to update soon.
Click to expand...
Click to collapse
I'm now on the fence about reverting to the longer standing 2.8.7 version of TWRP, but since the primary maintainer for my Otus CM12.1 and CM13 ROMS (@squid2) also creates the build of TWRP and has included in his 3.0.2 version some forward fixes that might be better for CM13 especially where encryption is used, I have been updating it. A consideration in this regard is; what if it was not the different version of TWRP that caused this but rather a one-time instance of something that went wrong in the act of flashing it - which I would be more at risk of because I do occasionally update TWRP.
Hmmmm...I did recently restore a nandroid of stock Moto L 5.0.2 then flashed stock recovery in an attempt to install a pending L5.1 OTA (Moto finally released it!) which failed AFAIK due to unlocked bootloader, then I flashed TWRP 3.0.2 and restored a CM12.1 nandroid. If that was a factor it merely planted the seed of the problem but did not grow into the problem until some other later action .
[] AL [] said:
As for apps, what I find strange is that even a format didn't fix things up with it.
Click to expand...
Click to collapse
The drive became un-writable in every way including the ability to format or change any properties of the drive in any drive/partition manager even though the data was all there in perfect shape. Ironically the problem with the drive is now protecting the data
[] AL [] said:
...I would hope to believe that a file explorer alone can not mess it up THAT much alone...
Click to expand...
Click to collapse
Likewise but at this point it would not surprise me considering that Android is a bit fast and loose with more basal aspects of the system including drive management.
Ultramanoid said:
I've used extensively SanDisk 64 GB microsdxc cards with Android. Given all the information you've given, I'd lean towards physical card failure.
It happens. In my experience, very rarely, but it does.
If the same thing happens again to another of your cards anytime soon, that's when you should start a serious investigation about it.
To be honest I've had more smartphones failing on me for a myriad different reasons in the last few years than problems with a card from a reliable manufacturer.
I have washed some of these cards in the washing machine by mistake, and I've used some intensively non-stop every single day for two or three years without an issue. I've run OSes from them often, and always replaced them for another because of speed or space concerns, very rarely because of failure.
They are incredibly resilient. And yet sometimes ( again, rarely ) one will spit input / output errors, or simply die on me, no matter what the format, filesystem, or OS. In fact it happened once with a brand new card that I had just used for a couple of weeks, the irony...
Click to expand...
Click to collapse
Good points. Thanks! I've had similar experiences with Micro SDs surviving through accidental washings as well as heavy use as USB boot drives running various utilities or Linux distributions (one of which had a persistent cache cache right on the card - thats a lot of read/writes) and I can't remember encountering a corrupted SD card that was not physically damaged.
That being said I did once support an outdoor system of over 300 units each of which ran off of a proprietary Linux system on an 8GB SD card where SD card corruption was not uncommon but those "devices" were exposed to thermal extremes, traffic vibrations, and poor quality field work and remote management the likes of which our devices rarely experience.
At first I was leaning toward SD card corruption but now wonder if this was an accidental digital write-protect, perhaps caused by an extremely localized bit of SD card corruption... or something like that... and that is an area where android is faster and looser than many other device/OS combinations.
What is the result of fsck with Linux ?
Ultramanoid said:
What is the result of fsck with Linux ?
Click to expand...
Click to collapse
Similar to Windows chkdsk; In Ubuntu 14.x Live USB boot, fsck (supposedly) reclaims lost clusters, and reports "free cluster summary wrong...". When option to fix is selected the command cannot gain write access to the drive. Re-scan verifies same errors persist.
Here's an idea that worked for me once with a card that refused to be formatted on Linux and OS X; try with a digital camera or DSLR, you may need a micro to SD adapter.
In that case though, mine was a defective card indeed. The camera did format it, and was usable for a little while, before giving errors again, and I discarded it definitely.
Edit : to be precise, the camera did not recognize it and offered to format it ( to FAT being an old DSLR, but a new camera might go for exFAT, and you already suspect foul play because of exFAT ), which worked, and then I could format it again ( ext4 ) in Linux. As mentioned, the card failed again soon afterwards anyway.
Ultramanoid said:
Here's an idea that worked for me once with a card that refused to be formatted on Linux and OS X; try with a digital camera or DSLR, you may need a micro to SD adapter.
In that case though, mine was a defective card indeed. The camera did format it, and was usable for a little while, before giving errors again, and I discarded it definitely.
Edit : to be precise, the camera did not recognize it and offered to format it ( to FAT being an old DSLR, but a new camera might go for exFAT, and you already suspect foul play because of exFAT ), which worked, and then I could format it again ( ext4 ) in Linux. As mentioned, the card failed again soon afterwards anyway.
Click to expand...
Click to collapse
I tried that yesterday in a relatively new camera that is supposedly capable of handling 64GB SDXC but the camera reports that the card could not be used but offered not other information.
As to exFAT - this correction to my initial assessment of the situation: The reason Windows 7 only offers NTFS and exFAT as formatting options is not necessarily because the drive is damaged or had a read only flag applied (although both off those thing now seem likely*) but rather because Windows 7 cannot format USB drives over 32GB as FAT32 even though it can mount and use them if they were formatted elsewhere. This does not really change things other than meaning that the available Windows formatting options are not informative.
* I just called SanDisk support and learned that the card supposedly has some sort of data preservation feature where; when an imminent potential failure is detected the card is indeed digitally write protected. This might mean that there is a way to undo the digital protection although that would put the data risk and the protection is non-standard as the Windows Diskpart command line utility does not show the disk or the volume as write protected.SanDisk even offered to replace the card but I declined (for now) because I want to hack at it some more. At least there now seems to be an understandable mechanism for how this happened.
Thanks for throwing some thought into it
It's interesting, the card I mentioned was a 64GB one, but the camera formatted it to FAT creating a 32GB partition, same limit as Windows. It pretty much ignored the other half of the card that showed up just as free space, but it also undid whatever was blocking the formatting before, which may have been that protection scheme from SanDisk as in your case. Good to learn about that.
Interesting...
I have the same issue with my Samsung 64gb sd. I was moving a zip file from internal sd to external sd with ES File Explorer and all of a sudden my phone froze and I had to hard reset. When I rebooted external was screwed. I have been looking for days for a fix and have come up with nothing. TWRP can see the card but no values. Please any help would be very much appreciated because I have ALL the pictures of my 2 week old son stored in ext sd.
noob4598 said:
I have the same issue with my Samsung 64gb sd. I was moving a zip file from internal sd to external sd with ES File Explorer and all of a sudden my phone froze and I had to hard reset. When I rebooted external was screwed. I have been looking for days for a fix and have come up with nothing. TWRP can see the card but no values. Please any help would be very much appreciated because I have ALL the pictures of my 2 week old son stored in ext sd.
Click to expand...
Click to collapse
See if this helps. Read through it, it has allot of helpful information.
http://forum.xda-developers.com/showthread.php?t=1192508
noob4598 said:
I have the same issue with my Samsung 64gb sd. I was moving a zip file from internal sd to external sd with ES File Explorer and all of a sudden my phone froze and I had to hard reset. When I rebooted external was screwed. I have been looking for days for a fix and have come up with nothing. TWRP can see the card but no values. Please any help would be very much appreciated because I have ALL the pictures of my 2 week old son stored in ext sd.
Click to expand...
Click to collapse
The incident about which I created this thread was sudden as yours was. Try viewing the contents of the SD card in a card-reader on a computer. If you can see the contents and copy to the computer but cannot write to the SD card you may be experiencing the same issue describe in the OP of this thread (irreversible dirty bit write protection due to impending failure detected), in which case you would have to backup the data on the card and get a new one. Also, it is best to keep internal/adoptable storage completely out of this equation as that re-formats and encrypts the SD card.
@MatisyahuSerious
Since this was a bit OT for LOS I've expanded upon this post (https://forum.xda-developers.com/showpost.php?p=71903594&postcount=4155) here where the reply is less off topic.
Off course there are many other bad things that can happen to SD cards, and frequent ROM flashing and TiBU backups put a particular stress on them. Another factor, at least in my case, is that when a high speed SD card (eg Sandisk Ultra red/grey) is used in a USB 3 port (to move data much quicker than MTP) the SD card gets so hot that the painted logo scorches and changes color. Those thermal cycles cant be good for the cards either. I've had 3 go bad in about 6 years, one in the manner described in linked post.
A bit of somewhat related OT: For what this is worth I once supported a system which ran Linux based OS from 8GB SD cards and the most frequent fix was to replace corrupted SD cards. SD cards have gotten better, and some brands may be better than others, but they were not originally designed to handle so much fast R/W and IMO the SD industry is still catching up.
I have Toshiba 64GB sdcard class 10 and noticed that is too slow in writing so I made some tests on it.
In PC I got 21 mb/s.
In Huawei P8 I got 19 mb/s.
In my Z2 I got 3~4 mb/s.
So I tried the Huawei's sdcard 32GB U1 in my Z2 and I got 4 mb/s.
At recording videos in Z2 there's a delay about 3 sec to save and for deleting somethings it takes a lot of time. So the problem is in my Z2 I think. Could you please explain what is a solution for this?
My Z2 is 6 months old, 6.0.1 mm
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try kernel auditor there is an option which speed sd card, go to I/O scheduler and set read-ahead for the external storage to 4096 and apply on boot.4096 is a good value because your sd card is class 10.
I think it depends on how you bind in your device.
F.e. in Titanium Backup I use 'External Storage', that's the fastest option.
If you are on stock ROM, there is no need to modify anything.
rocker00 said:
try kernel auditor there is an option which speed sd card, go to I/O scheduler and set read-ahead for the external storage to 4096 and apply on boot.4096 is a good value because your sd card is class 10.
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Click to collapse
I tried it and it is 4096 and change it to lower value (512, 1024, 2048) and what I saw was same speed. I reflashed with flashtool and pcc but no luck. It was like this since the first minute when I bought my device.
bgumble said:
I think it depends on how you bind in your device.
F.e. in Titanium Backup I use 'External Storage', that's the fastest option.
If you are on stock ROM, there is no need to modify anything.
Click to expand...
Click to collapse
Sent from my D6503 using XDA-Developers mobile app