zfs issue - disappearing data

Sat May 4 00:03:34 UTC 2013

Interesting.

Is that why zdb shows so many objects?

Is this a configuration mistake, and would it lead to data loss?

Can I provide any addition information ?

Mike C

On 5/3/2013 3:41 PM, Adam Nowacki wrote:
> Looks like we have a leak with extended attributes:
>
> # zfs create -o mountpoint=/test root/test
> # touch /test/file1
> # setextattr user test abc /test/file1
> # zdb root/test
>     Object  lvl   iblk   dblk  dsize  lsize   %full  type
>          8    1    16K    512      0    512    0.00  ZFS plain file
>          9    1    16K    512     1K    512  100.00  ZFS directory
>         10    1    16K    512    512    512  100.00  ZFS plain file
>
> object 8 - the file,
> object 9 - extended attributes directory,
> object 10 - value of the 'test' extended attribute
>
> # rm /test/file1
> # zdb root/test
>
>     Object  lvl   iblk   dblk  dsize  lsize   %full  type
>         10    1    16K    512    512    512  100.00  ZFS plain file
>
> objects 8 and 9 are deleted, object 10 is still there (leaked).
>
> On 2013-05-03 19:43, Mike Carlson wrote:
>> We had a critical issue with a zfs server that exports shares via samba
>> (3.5) last night
>>
>> system info:
>> uname -a
>>
>>     FreeBSD zfs-1.discdrive.bayphoto.com 9.1-RELEASE FreeBSD 9.1-RELEASE
>>     #0 r243825: Tue Dec  4 09:23:10 UTC 2012
>>     root at farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64
>>
>> zpool history:
>>
>>     History for 'data':
>>     2013-02-25.17:11:37 zpool create data raidz /dev/gpt/disk1.nop
>>     /dev/gpt/disk2.nop /dev/gpt/disk3.nop /dev/gpt/disk4.nop
>>     2013-02-25.17:11:41 zpool add data raidz /dev/gpt/disk5.nop
>>     /dev/gpt/disk6.nop /dev/gpt/disk7.nop /dev/gpt/disk8.nop
>>     2013-02-25.17:11:47 zpool add data raidz /dev/gpt/disk9.nop
>>     /dev/gpt/disk10.nop /dev/gpt/disk11.nop /dev/gpt/disk12.nop
>>     2013-02-25.17:11:53 zpool add data raidz /dev/gpt/disk13.nop
>>     /dev/gpt/disk14.nop /dev/gpt/disk15.nop /dev/gpt/disk16.nop
>>     2013-02-25.17:11:57 zpool add data raidz /dev/gpt/disk17.nop
>>     /dev/gpt/disk18.nop /dev/gpt/disk19.nop /dev/gpt/disk20.nop
>>     2013-02-25.17:12:02 zpool add data raidz /dev/gpt/disk21.nop
>>     /dev/gpt/disk22.nop /dev/gpt/disk23.nop /dev/gpt/disk24.nop
>>     2013-02-25.17:12:08 zpool add data spare /dev/gpt/disk25.nop
>>     /dev/gpt/disk26.nop
>>     2013-02-25.17:12:15 zpool add data log /dev/gpt/log.nop
>>     2013-02-25.17:12:19 zfs set checksum=fletcher4 data
>>     2013-02-25.17:12:22 zfs set compression=lzjb data
>>     2013-02-25.17:12:25 zfs set aclmode=passthrough data
>>     2013-02-25.17:12:30 zfs set aclinherit=passthrough data
>>     2013-02-25.17:13:25 zpool export data
>>     2013-02-25.17:15:33 zpool import -d /dev/gpt data
>>     2013-03-01.12:31:58 zpool add data cache /dev/gpt/cache.nop
>>     2013-03-15.12:22:22 zfs create data/XML_WORKFLOW
>>     2013-03-27.12:05:42 zfs create data/IMAGEQUIX
>>     2013-03-27.13:32:54 zfs create data/ROES_ORDERS
>>     2013-03-27.13:32:59 zfs create data/ROES_PRINTABLES
>>     2013-03-27.13:33:21 zfs destroy data/ROES_PRINTABLES
>>     2013-03-27.13:33:26 zfs create data/ROES_PRINTABLE
>>
>> We had a file structure drop off:
>>
>> /data/XML_WORKFLOW/XML_ORDERS/
>>
>> around 5/2/2012 @ 17:00
>>
>> In that directory, there were a few thousand directories (containing
>> images and a couple metadata text/xml files)
>>
>> What is odd, is doing a du -h in the parent XML_WORKFLOW directory, only
>> reports ~150MB:
>>
>>       # find . -type f |wc -l
>>     86
>>     # du -sh .
>>     130M .
>>
>>
>> however, df reports 1.5GB:
>>
>>     # df -h .
>>     Filesystem Size Used Avail Capacity Mounted on
>>     data/XML_WORKFLOW 28T 1.5G 28T 0% /data/XML_WORKFLOW
>>
>> zdb -d shows:
>>
>>     # zdb -d data/XML_WORKFLOW
>>     Dataset data/XML_WORKFLOW [ZPL], ID 139, cr_txg 339633, 1.53G,
>>     212812 objects
>>
>> Digging further into zdb, the path is missing for most of those objects:
>>
>>     # zdb -ddddd data/XML_WORKFLOW 635248
>>     Dataset data/XML_WORKFLOW [ZPL], ID 139, cr_txg 339633, 1.53G,
>>     212812 objects, rootbp DVA[0]=<5:b274264000:2000>
>>     DVA[1]=<0:b4d81a8000:2000> [L0 DMU objset] fletcher4 lzjb LE
>>     contiguous unique double size=800L/200P birth=1202311L/1202311P
>>     fill=212812 
>> cksum=16d24fb5aa:6c2e0aff6bc:129af90fe2eff:2612f938c5292b
>>
>>     Object lvl iblk dblk dsize lsize %full type
>>     635248 1 16K 512 6.00K 512 100.00 ZFS plain file
>>     168 bonus System attributes
>>     dnode flags: USED_BYTES USERUSED_ACCOUNTED
>>     dnode maxblkid: 0
>>     path ???<object#635248>
>>     uid 11258
>>     gid 10513
>>     atime Thu May 2 17:31:26 2013
>>     mtime Thu May 2 17:31:26 2013
>>     ctime Thu May 2 17:31:26 2013
>>     crtime Thu May 2 17:13:58 2013
>>     gen 1197180
>>     mode 100600
>>     size 52
>>     parent 635247
>>     links 1
>>     pflags 40800000005
>>     Indirect blocks:
>>     0 L0 3:a9da05a000:2000 200L/200P F=1 B=1197391/1197391
>>
>>     segment [0000000000000000, 0000000000000200) size 512
>>
>> The application that writes to this volume runs on a windows client, so
>> far, it has exhibited identical behavior across two zfs servers, but not
>> on a generic windows server 2003 network share.
>>
>> The question is, what is happening to the data. Is it a samba issue? Is
>> it ZFS? I've enabled the samba full_audit module to track file
>> deletions, so I should have more information on that side.
>>
>> If anyone has seen similar behavior please let me know
>>
>> Mike C
>

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