zfs issue - disappearing data

Mike Carlson mike at bayphoto.com
Sat May 4 23:33:15 UTC 2013


Just to update the list and close this thread, this issue as it turns 
out was not ZFS related, but the application that read/writes to the 
CIFS share.

Good to know about the leaking extended attributes though, and of 
course, the great responses from Adam and Jeremy.

Thanks again,

Mike C

On 5/3/2013 5:03 PM, Mike Carlson wrote:
> 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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