Re: how to verify bitrot signed file manually?

[Amudhan P <amudhan83@xxxxxxxxx>]

any update?.  

why is it marked bad? 

Any way to find out what happened to the file?

On Tue, Oct 3, 2017 at 12:44 PM, Amudhan P <amudhan83@xxxxxxxxx> wrote:

 

my volume is distributed disperse volume 8+2 EC. 

file1 and file2 are different files lying in same brick. I am able to read the file from mount point without any issue because of EC it reads rest of the available blocks in other nodes.

my question is "file1" sha256 value matches bitrot signature value but still, it is also marked as bad by scrubber daemon. why is that?

On Fri, Sep 29, 2017 at 12:52 PM, Kotresh Hiremath Ravishankar <khiremat@xxxxxxxxxx> wrote:

Hi Amudhan,

Sorry for the late response as I was busy with other things. You are right bitrot uses sha256 for checksum.

If file-1, file-2 are marked bad, the I/O should be errored out with EIO. If that is not happening, we need

to look further into it. But what's the file contents of file-1 and file-2 on the replica bricks ? Are they

matching ?

Thanks and Regards,

Kotresh HR

On Mon, Sep 25, 2017 at 4:19 PM, Amudhan P <amudhan83@xxxxxxxxx> wrote:

resending mail.

On Fri, Sep 22, 2017 at 5:30 PM, Amudhan P <amudhan83@xxxxxxxxx> wrote:

ok, from bitrot code I figured out gluster using sha256 hashing algo.

Now coming to the problem, during scrub run in my cluster some of my files were marked as bad in few set of nodes. 

I just wanted to confirm bad file. so, I have used "sha256sum" tool in Linux to manually get file hash.

here is the result.

file-1, file-2 marked as bad by scrub and file-3 is healthy.

file-1 sha256 and bitrot signature value matches but still it's been marked as bad.

file-2 sha256 and bitrot signature value don't match, could be a victim of bitrot or bitflip.file is still readable without any issue and no errors found in the drive.

file-3 sha256 and bitrot signature matches and healthy.

file-1 output from 

"sha256sum" = "71eada9352b1352aaef0f806d3d561768ce2df905ded1668f665e06eca2d0bd4"

"getfattr -m. -e hex -d "

# file: file-1

trusted.bit-rot.bad-file=0x3100

trusted.bit-rot.signature=0x01020000000000000071eada9352b1352aaef0f806d3d561768ce2df905ded1668f665e06eca2d0bd4

trusted.bit-rot.version=0x020000000000000058e4f3b40006793d

trusted.ec.config=0x0000080a02000200

trusted.ec.dirty=0x00000000000000000000000000000000

trusted.ec.size=0x0000000718996701

trusted.ec.version=0x0000000000038c4c0000000000038c4d

trusted.gfid=0xf078a24134fe4f9bb953eca8c28dea9a

output scrub log:

[2017-09-02 13:02:20.311160] A [MSGID: 118023] [bit-rot-scrub.c:244:bitd_compare_ckum] 0-qubevaultdr-bit-rot-0: CORRUPTION DETECTED: Object /file-1 {Brick: /media/disk16/brick16 | GFID: f078a241-34fe-4f9b-b953-eca8c28dea9a}

[2017-09-02 13:02:20.311579] A [MSGID: 118024] [bit-rot-scrub.c:264:bitd_compare_ckum] 0-qubevaultdr-bit-rot-0: Marking /file-1 [GFID: f078a241-34fe-4f9b-b953-eca8c28dea9a | Brick: /media/disk16/brick16] as corrupted..

file-2 output from 

"sha256sum" = "c41ef9c81faed4f3e6010ea67984c3cfefd842f98ee342939151f9250972dcda"

"getfattr -m. -e hex -d "

# file: file-2

trusted.bit-rot.bad-file=0x3100

trusted.bit-rot.signature=0x0102000000000000009162cb17d4f0bee676fcb7830c5286d05b8e8940d14f3d117cb90b7b1defc129

trusted.bit-rot.version=0x020000000000000058e4f3b400019bb2

trusted.ec.config=0x0000080a02000200

trusted.ec.dirty=0x00000000000000000000000000000000

trusted.ec.size=0x00000000403433f6

trusted.ec.version=0x000000000000201a000000000000201b

trusted.gfid=0xa50012b0a632477c99232313928d239a

output scrub log:

[2017-09-02 05:18:14.003156] A [MSGID: 118023] [bit-rot-scrub.c:244:bitd_compare_ckum] 0-qubevaultdr-bit-rot-0: CORRUPTION DETECTED: Object /file-2 {Brick: /media/disk13/brick13 | GFID: a50012b0-a632-477c-9923-2313928d239a}

[2017-09-02 05:18:14.006629] A [MSGID: 118024] [bit-rot-scrub.c:264:bitd_compare_ckum] 0-qubevaultdr-bit-rot-0: Marking /file-2 [GFID: a50012b0-a632-477c-9923-2313928d239a | Brick: /media/disk13/brick13] as corrupted..

file-3 output from 

"sha256sum" = "a590735b3c8936cc7ca9835128a19c38a3f79c8fd53fddc031a9349b7e273f27"

"getfattr -m. -e hex -d "

# file: file-3

trusted.bit-rot.signature=0x010200000000000000a590735b3c8936cc7ca9835128a19c38a3f79c8fd53fddc031a9349b7e273f27

trusted.bit-rot.version=0x020000000000000058e4f3b400019bb2

trusted.ec.config=0x0000080a02000200

trusted.ec.dirty=0x00000000000000000000000000000000

trusted.ec.size=0x000000003530fc96

trusted.ec.version=0x0000000000001a980000000000001a99

trusted.gfid=0x10d8920e42cd42cf9448b8bf3941c192

most of the bitrot bad files are in the set of new nodes and data were uploaded using gluster 3.10.1. no drive issues are any kind of error msgs in logs.

what could be gone wrong?

regards

Amudhan

On Thu, Sep 21, 2017 at 1:23 PM, Amudhan P <amudhan83@xxxxxxxxx> wrote:

Hi,

I have a file in my brick which was signed by bitrot and latter when running scrub it was marked as bad.

Now, I want to verify file again manually. just to clarify my doubt

how can I do this?

regards

Amudhan

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Thanks and Regards,

Kotresh H R

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