Linux: Alternative to UBIFS on MLC NAND
The status of UBIFS in Linux on top of MLC NAND has never been exactly perfect. And while this entry has now been removed from the FAQ nowadays, the support for UBIFS on top of MLC NAND has now been officially reported as unsupported:
- ubi: Reject MLC NAND
Full thread on patchwork.kernel.org:
- https://patchwork.kernel.org/patch/10256063/
So I am now looking for a long term filesystem replacement for a MLC NAND as found on a MIPS Creator CI20:
- CI20_Hardware: ROM/NAND
This is a Samsung K9GBG08UOA NAND flash and it does not appear that there is a way to put this device in SLC mode.
It seems that jffs2 is also not an alternative:
- jffs2: do not support the MLC nand
Is there any other alternative filesystem (possibly with comparable performance) ?
linux filesystems ubifs
asked Jun 8 '18 at 7:24
malatmalat
539723
add a comment |
The status of UBIFS in Linux on top of MLC NAND has never been exactly perfect. And while this entry has now been removed from the FAQ nowadays, the support for UBIFS on top of MLC NAND has now been officially reported as unsupported:
- ubi: Reject MLC NAND
Full thread on patchwork.kernel.org:
- https://patchwork.kernel.org/patch/10256063/
So I am now looking for a long term filesystem replacement for a MLC NAND as found on a MIPS Creator CI20:
- CI20_Hardware: ROM/NAND
This is a Samsung K9GBG08UOA NAND flash and it does not appear that there is a way to put this device in SLC mode.
It seems that jffs2 is also not an alternative:
- jffs2: do not support the MLC nand
Is there any other alternative filesystem (possibly with comparable performance) ?
linux filesystems ubifs
asked Jun 8 '18 at 7:24
malatmalat
539723
This is worrying. We have products using MLC nand and UBIFS. It is not required in near future however now upgrading to latest kernel is tricky.
– AnkurTank
Jun 18 '18 at 13:07
1
@AnkurTank UBIFS removal patch was send CC to stable@v.k.o so it should be backported at some point.
– malat
Jun 18 '18 at 13:14
oh so do you mean even LTS kernels will also add that patch ?
– AnkurTank
Jun 18 '18 at 13:23
add a comment |
The status of UBIFS in Linux on top of MLC NAND has never been exactly perfect. And while this entry has now been removed from the FAQ nowadays, the support for UBIFS on top of MLC NAND has now been officially reported as unsupported:
- ubi: Reject MLC NAND
Full thread on patchwork.kernel.org:
- https://patchwork.kernel.org/patch/10256063/
So I am now looking for a long term filesystem replacement for a MLC NAND as found on a MIPS Creator CI20:
- CI20_Hardware: ROM/NAND
This is a Samsung K9GBG08UOA NAND flash and it does not appear that there is a way to put this device in SLC mode.
It seems that jffs2 is also not an alternative:
- jffs2: do not support the MLC nand
Is there any other alternative filesystem (possibly with comparable performance) ?
linux filesystems ubifs
asked Jun 8 '18 at 7:24
malatmalat
539723
The status of UBIFS in Linux on top of MLC NAND has never been exactly perfect. And while this entry has now been removed from the FAQ nowadays, the support for UBIFS on top of MLC NAND has now been officially reported as unsupported:
- ubi: Reject MLC NAND
Full thread on patchwork.kernel.org:
- https://patchwork.kernel.org/patch/10256063/
So I am now looking for a long term filesystem replacement for a MLC NAND as found on a MIPS Creator CI20:
- CI20_Hardware: ROM/NAND
This is a Samsung K9GBG08UOA NAND flash and it does not appear that there is a way to put this device in SLC mode.
It seems that jffs2 is also not an alternative:
- jffs2: do not support the MLC nand
Is there any other alternative filesystem (possibly with comparable performance) ?
linux filesystems ubifs
linux filesystems ubifs
asked Jun 8 '18 at 7:24
malatmalat
539723
asked Jun 8 '18 at 7:24
malatmalat
539723
edited Jun 18 '18 at 12:30
malat
asked Jun 8 '18 at 7:24
malatmalat
539723
asked Jun 8 '18 at 7:24
malatmalat
539723
asked Jun 8 '18 at 7:24
malatmalat
539723
539723
This is worrying. We have products using MLC nand and UBIFS. It is not required in near future however now upgrading to latest kernel is tricky.
– AnkurTank
Jun 18 '18 at 13:07
1
@AnkurTank UBIFS removal patch was send CC to stable@v.k.o so it should be backported at some point.
– malat
Jun 18 '18 at 13:14
oh so do you mean even LTS kernels will also add that patch ?
– AnkurTank
Jun 18 '18 at 13:23
add a comment |
This is worrying. We have products using MLC nand and UBIFS. It is not required in near future however now upgrading to latest kernel is tricky.
– AnkurTank
Jun 18 '18 at 13:07
1
@AnkurTank UBIFS removal patch was send CC to stable@v.k.o so it should be backported at some point.
– malat
Jun 18 '18 at 13:14
oh so do you mean even LTS kernels will also add that patch ?
– AnkurTank
Jun 18 '18 at 13:23
This is worrying. We have products using MLC nand and UBIFS. It is not required in near future however now upgrading to latest kernel is tricky.
– AnkurTank
Jun 18 '18 at 13:07
This is worrying. We have products using MLC nand and UBIFS. It is not required in near future however now upgrading to latest kernel is tricky.
– AnkurTank
Jun 18 '18 at 13:07
1
1
@AnkurTank UBIFS removal patch was send CC to stable@v.k.o so it should be backported at some point.
– malat
Jun 18 '18 at 13:14
@AnkurTank UBIFS removal patch was send CC to stable@v.k.o so it should be backported at some point.
– malat
Jun 18 '18 at 13:14
oh so do you mean even LTS kernels will also add that patch ?
– AnkurTank
Jun 18 '18 at 13:23
oh so do you mean even LTS kernels will also add that patch ?
– AnkurTank
Jun 18 '18 at 13:23
add a comment |
3 Answers
3
active
oldest
votes
If you have the option of including commercial software, Datalight currently still supports MLC. I have no idea how much it costs, or if there's a free-as-in-beer license for non-commercial use.
My only connection is that I'm on their mailing list and attended a couple of webinars. I've never used their products, so apply caveats and grains of salt accordingly. Good luck.
Related links, most-recent first:
- https://www.datalight.com/news/datalight-announces-ffxt-4.2
- https://www.datalight.com/blog/2018/06/13/linux-kernel-4.17-released/
- https://www.datalight.com/blog/2013/10/23/mtd-for-mlc-nand/
edited Jul 23 '18 at 17:52
slm♦
248k66517678
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
add a comment |
Is there any [Linux] filesystem ... [that supports] UBIFS on top of MLC NAND?
No;
As of Linux 4.17 there are no file systems that specifically handle MLC NAND.
Ideally the file system would not need to know about the storage medium because quirks and features should be transparently handled. Of course practically this is not true, but it is the only assumption one can make about future mediums, so it is not surprising that in Linux 4.17 jffs2 is the only file system to check;
> grep -lr MTD_MLCNANDFLASH fs
fs/jffs2/fs.c
and
find fs -maxdepth 1 -type d | wc -l
72
That means only 1 of ~70 file systems care about MLC.
I don't see anything on out-of-tree file systems like zfs either.
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
⅔ of your answer is a repeat of the code I already inspected from the Linux kernel, and referenced from my question. This is not an answer, but a rephrase.
– malat
Jul 10 '18 at 12:44
@malat I updated my answer to be more clear.
– user1133275
7 hours ago
add a comment |
So it seems that two options are possible:
- git revert b5094b7f135be and then,
wait for more work on MLC+NAND
The fact that MLC NANDs are not supported by UBI is not necessarily
definitive. I have a branch with all the work we've done to add MLC
support to UBI 2. If you have time to invest in it, feel free to
take over this work.
Anyway, the decision to remove this driver is not mine, and this patch
allows me to at least compile-test this driver.
Something to try out:
- ext4 atop the MTD block layer
answered Jul 13 '18 at 9:50
malatmalat
539723
1
the lack of wear-levelling in mtdblock, and its horrendous amplification for small writes, rather limits its applicability. that's before the MLC question... I guess the best hope is that the write amplification actually mitigates MLC program disturb :-D. But the lack of wear-levelling would rather worry me for "long term filesystem."
– sourcejedi
Jul 13 '18 at 12:00
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
If you have the option of including commercial software, Datalight currently still supports MLC. I have no idea how much it costs, or if there's a free-as-in-beer license for non-commercial use.
My only connection is that I'm on their mailing list and attended a couple of webinars. I've never used their products, so apply caveats and grains of salt accordingly. Good luck.
Related links, most-recent first:
- https://www.datalight.com/news/datalight-announces-ffxt-4.2
- https://www.datalight.com/blog/2018/06/13/linux-kernel-4.17-released/
- https://www.datalight.com/blog/2013/10/23/mtd-for-mlc-nand/
edited Jul 23 '18 at 17:52
slm♦
248k66517678
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
add a comment |
If you have the option of including commercial software, Datalight currently still supports MLC. I have no idea how much it costs, or if there's a free-as-in-beer license for non-commercial use.
My only connection is that I'm on their mailing list and attended a couple of webinars. I've never used their products, so apply caveats and grains of salt accordingly. Good luck.
Related links, most-recent first:
- https://www.datalight.com/news/datalight-announces-ffxt-4.2
- https://www.datalight.com/blog/2018/06/13/linux-kernel-4.17-released/
- https://www.datalight.com/blog/2013/10/23/mtd-for-mlc-nand/
edited Jul 23 '18 at 17:52
slm♦
248k66517678
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
add a comment |
If you have the option of including commercial software, Datalight currently still supports MLC. I have no idea how much it costs, or if there's a free-as-in-beer license for non-commercial use.
My only connection is that I'm on their mailing list and attended a couple of webinars. I've never used their products, so apply caveats and grains of salt accordingly. Good luck.
Related links, most-recent first:
- https://www.datalight.com/news/datalight-announces-ffxt-4.2
- https://www.datalight.com/blog/2018/06/13/linux-kernel-4.17-released/
- https://www.datalight.com/blog/2013/10/23/mtd-for-mlc-nand/
edited Jul 23 '18 at 17:52
slm♦
248k66517678
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
If you have the option of including commercial software, Datalight currently still supports MLC. I have no idea how much it costs, or if there's a free-as-in-beer license for non-commercial use.
My only connection is that I'm on their mailing list and attended a couple of webinars. I've never used their products, so apply caveats and grains of salt accordingly. Good luck.
Related links, most-recent first:
- https://www.datalight.com/news/datalight-announces-ffxt-4.2
- https://www.datalight.com/blog/2018/06/13/linux-kernel-4.17-released/
- https://www.datalight.com/blog/2013/10/23/mtd-for-mlc-nand/
edited Jul 23 '18 at 17:52
slm♦
248k66517678
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
edited Jul 23 '18 at 17:52
slm♦
248k66517678
edited Jul 23 '18 at 17:52
slm♦
248k66517678
edited Jul 23 '18 at 17:52
slm♦
248k66517678
248k66517678
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
answered Jul 23 '18 at 17:10
William DyeWilliam Dye
111
111
add a comment |
add a comment |
Is there any [Linux] filesystem ... [that supports] UBIFS on top of MLC NAND?
No;
As of Linux 4.17 there are no file systems that specifically handle MLC NAND.
Ideally the file system would not need to know about the storage medium because quirks and features should be transparently handled. Of course practically this is not true, but it is the only assumption one can make about future mediums, so it is not surprising that in Linux 4.17 jffs2 is the only file system to check;
> grep -lr MTD_MLCNANDFLASH fs
fs/jffs2/fs.c
and
find fs -maxdepth 1 -type d | wc -l
72
That means only 1 of ~70 file systems care about MLC.
I don't see anything on out-of-tree file systems like zfs either.
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
⅔ of your answer is a repeat of the code I already inspected from the Linux kernel, and referenced from my question. This is not an answer, but a rephrase.
– malat
Jul 10 '18 at 12:44
@malat I updated my answer to be more clear.
– user1133275
7 hours ago
add a comment |
Is there any [Linux] filesystem ... [that supports] UBIFS on top of MLC NAND?
No;
As of Linux 4.17 there are no file systems that specifically handle MLC NAND.
Ideally the file system would not need to know about the storage medium because quirks and features should be transparently handled. Of course practically this is not true, but it is the only assumption one can make about future mediums, so it is not surprising that in Linux 4.17 jffs2 is the only file system to check;
> grep -lr MTD_MLCNANDFLASH fs
fs/jffs2/fs.c
and
find fs -maxdepth 1 -type d | wc -l
72
That means only 1 of ~70 file systems care about MLC.
I don't see anything on out-of-tree file systems like zfs either.
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
⅔ of your answer is a repeat of the code I already inspected from the Linux kernel, and referenced from my question. This is not an answer, but a rephrase.
– malat
Jul 10 '18 at 12:44
@malat I updated my answer to be more clear.
– user1133275
7 hours ago
add a comment |
Is there any [Linux] filesystem ... [that supports] UBIFS on top of MLC NAND?
No;
As of Linux 4.17 there are no file systems that specifically handle MLC NAND.
Ideally the file system would not need to know about the storage medium because quirks and features should be transparently handled. Of course practically this is not true, but it is the only assumption one can make about future mediums, so it is not surprising that in Linux 4.17 jffs2 is the only file system to check;
> grep -lr MTD_MLCNANDFLASH fs
fs/jffs2/fs.c
and
find fs -maxdepth 1 -type d | wc -l
72
That means only 1 of ~70 file systems care about MLC.
I don't see anything on out-of-tree file systems like zfs either.
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
Is there any [Linux] filesystem ... [that supports] UBIFS on top of MLC NAND?
No;
As of Linux 4.17 there are no file systems that specifically handle MLC NAND.
Ideally the file system would not need to know about the storage medium because quirks and features should be transparently handled. Of course practically this is not true, but it is the only assumption one can make about future mediums, so it is not surprising that in Linux 4.17 jffs2 is the only file system to check;
> grep -lr MTD_MLCNANDFLASH fs
fs/jffs2/fs.c
and
find fs -maxdepth 1 -type d | wc -l
72
That means only 1 of ~70 file systems care about MLC.
I don't see anything on out-of-tree file systems like zfs either.
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
edited 7 hours ago
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
answered Jul 8 '18 at 15:22
user1133275user1133275
2,874620
2,874620
⅔ of your answer is a repeat of the code I already inspected from the Linux kernel, and referenced from my question. This is not an answer, but a rephrase.
– malat
Jul 10 '18 at 12:44
@malat I updated my answer to be more clear.
– user1133275
7 hours ago
add a comment |
⅔ of your answer is a repeat of the code I already inspected from the Linux kernel, and referenced from my question. This is not an answer, but a rephrase.
– malat
Jul 10 '18 at 12:44
@malat I updated my answer to be more clear.
– user1133275
7 hours ago
⅔ of your answer is a repeat of the code I already inspected from the Linux kernel, and referenced from my question. This is not an answer, but a rephrase.
– malat
Jul 10 '18 at 12:44
⅔ of your answer is a repeat of the code I already inspected from the Linux kernel, and referenced from my question. This is not an answer, but a rephrase.
– malat
Jul 10 '18 at 12:44
@malat I updated my answer to be more clear.
– user1133275
7 hours ago
@malat I updated my answer to be more clear.
– user1133275
7 hours ago
add a comment |
So it seems that two options are possible:
- git revert b5094b7f135be and then,
wait for more work on MLC+NAND
The fact that MLC NANDs are not supported by UBI is not necessarily
definitive. I have a branch with all the work we've done to add MLC
support to UBI 2. If you have time to invest in it, feel free to
take over this work.
Anyway, the decision to remove this driver is not mine, and this patch
allows me to at least compile-test this driver.
Something to try out:
- ext4 atop the MTD block layer
answered Jul 13 '18 at 9:50
malatmalat
539723
1
the lack of wear-levelling in mtdblock, and its horrendous amplification for small writes, rather limits its applicability. that's before the MLC question... I guess the best hope is that the write amplification actually mitigates MLC program disturb :-D. But the lack of wear-levelling would rather worry me for "long term filesystem."
– sourcejedi
Jul 13 '18 at 12:00
add a comment |
So it seems that two options are possible:
- git revert b5094b7f135be and then,
wait for more work on MLC+NAND
The fact that MLC NANDs are not supported by UBI is not necessarily
definitive. I have a branch with all the work we've done to add MLC
support to UBI 2. If you have time to invest in it, feel free to
take over this work.
Anyway, the decision to remove this driver is not mine, and this patch
allows me to at least compile-test this driver.
Something to try out:
- ext4 atop the MTD block layer
answered Jul 13 '18 at 9:50
malatmalat
539723
1
the lack of wear-levelling in mtdblock, and its horrendous amplification for small writes, rather limits its applicability. that's before the MLC question... I guess the best hope is that the write amplification actually mitigates MLC program disturb :-D. But the lack of wear-levelling would rather worry me for "long term filesystem."
– sourcejedi
Jul 13 '18 at 12:00
add a comment |
So it seems that two options are possible:
- git revert b5094b7f135be and then,
wait for more work on MLC+NAND
The fact that MLC NANDs are not supported by UBI is not necessarily
definitive. I have a branch with all the work we've done to add MLC
support to UBI 2. If you have time to invest in it, feel free to
take over this work.
Anyway, the decision to remove this driver is not mine, and this patch
allows me to at least compile-test this driver.
Something to try out:
- ext4 atop the MTD block layer
answered Jul 13 '18 at 9:50
malatmalat
539723
So it seems that two options are possible:
- git revert b5094b7f135be and then,
wait for more work on MLC+NAND
The fact that MLC NANDs are not supported by UBI is not necessarily
definitive. I have a branch with all the work we've done to add MLC
support to UBI 2. If you have time to invest in it, feel free to
take over this work.
Anyway, the decision to remove this driver is not mine, and this patch
allows me to at least compile-test this driver.
Something to try out:
- ext4 atop the MTD block layer
answered Jul 13 '18 at 9:50
malatmalat
539723
answered Jul 13 '18 at 9:50
malatmalat
539723
answered Jul 13 '18 at 9:50
malatmalat
539723
answered Jul 13 '18 at 9:50
malatmalat
539723
539723
1
the lack of wear-levelling in mtdblock, and its horrendous amplification for small writes, rather limits its applicability. that's before the MLC question... I guess the best hope is that the write amplification actually mitigates MLC program disturb :-D. But the lack of wear-levelling would rather worry me for "long term filesystem."
– sourcejedi
Jul 13 '18 at 12:00
add a comment |
1
the lack of wear-levelling in mtdblock, and its horrendous amplification for small writes, rather limits its applicability. that's before the MLC question... I guess the best hope is that the write amplification actually mitigates MLC program disturb :-D. But the lack of wear-levelling would rather worry me for "long term filesystem."
– sourcejedi
Jul 13 '18 at 12:00
1
1
the lack of wear-levelling in mtdblock, and its horrendous amplification for small writes, rather limits its applicability. that's before the MLC question... I guess the best hope is that the write amplification actually mitigates MLC program disturb :-D. But the lack of wear-levelling would rather worry me for "long term filesystem."
– sourcejedi
Jul 13 '18 at 12:00
the lack of wear-levelling in mtdblock, and its horrendous amplification for small writes, rather limits its applicability. that's before the MLC question... I guess the best hope is that the write amplification actually mitigates MLC program disturb :-D. But the lack of wear-levelling would rather worry me for "long term filesystem."
– sourcejedi
Jul 13 '18 at 12:00
add a comment |
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This is worrying. We have products using MLC nand and UBIFS. It is not required in near future however now upgrading to latest kernel is tricky.
– AnkurTank
Jun 18 '18 at 13:07
1
@AnkurTank UBIFS removal patch was send CC to stable@v.k.o so it should be backported at some point.
– malat
Jun 18 '18 at 13:14
oh so do you mean even LTS kernels will also add that patch ?
– AnkurTank
Jun 18 '18 at 13:23