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ZFS - Directory Contents vanished
Posted: 19 Jul 2013 13:29
by Tschuki
Hey guys,
so I recently discovered that the contents of one of my ZFS RaidZ1 directory are empty now.
Since there were quite some important data in it, I was wondering how I can restore the contents?
Some Facts:
- RAIDZ1 ZFS array with 6x2TB SAMSUNG HD204UI
Code: Select all
pool: RAIDZ1
state: ONLINE
scan: resilvered 300K in 0h0m with 0 errors on Fri Jul 19 13:04:06 2013
config:
NAME STATE READ WRITE CKSUM
RAIDZ1 ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
ada0 ONLINE 0 0 0
ada2 ONLINE 0 0 0
ada1 ONLINE 0 0 0
ada3 ONLINE 0 0 0
ada4 ONLINE 0 0 0
ada5 ONLINE 0 0 0
errors: No known data errors
Here is what I did:
- Since I use the SAMSUNG HD204UI 2TB disks - I did a firmware upgrade to enable a safe S.M.A.R.T. Monitoring
- I did on all of them
- So my dev/ada1 got his
Code: Select all
197 Current_Pending_Sector 0x0032 100 100 000 Old_age Always - 1
- I googled a bit and found out, I shoud run a LONG selftest, which will provide me the faulty sector, which I will rewrite and the problem should be fixed
- Here are the results of the tests:
Code: Select all
SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Short offline Completed without error 00% 15813 -
# 2 Short offline Completed without error 00% 15813 -
# 3 Extended offline Completed without error 00% 15807 -
# 4 Short offline Completed without error 00% 15790 -
- So the long selftest doesn't show anything abnormal, but the error is still there.
- As you can see, I tried to offline and online the disk but there is a small amount of resilvering done and everything is normal again
I'd like to reformat the disk and integrate it back into the array. How can I do this?
I get the feeling, that the contents are forever lost 
and the faulty sector is somehow responsible, since I can see the empty directory and my AFP has already made a new ".AppleDouble" directory in it.
Do you have any ideas to help me?
Thanks in advance!
Yours Tschuki
Re: ZFS - Directory Contents vanished
Posted: 22 Jul 2013 23:02
by Onichan
No idea about this firmware issue, but if you are using RAIDZ1 then a single drive messing-up wouldn't cause data-loss. So I expect something else is the cause of your empty directory.
Re: ZFS - Directory Contents vanished
Posted: 22 Jul 2013 23:23
by Tschuki
Hey Onichan,
thx for your reply!
Since my 1st post I found the reason....just a misclick, where a directory was moved into another. Fairly stupid
BUT can you explain to me, why my LONG SmartCTL Scan yields no results?
See my smartctl -a output here:
Code: Select all
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x002f 100 100 051 Pre-fail Always - 202
2 Throughput_Performance 0x0026 055 055 000 Old_age Always - 18451
3 Spin_Up_Time 0x0023 069 068 025 Pre-fail Always - 9695
4 Start_Stop_Count 0x0032 098 098 000 Old_age Always - 2655
5 Reallocated_Sector_Ct 0x0033 252 252 010 Pre-fail Always - 0
7 Seek_Error_Rate 0x002e 252 252 051 Old_age Always - 0
8 Seek_Time_Performance 0x0024 252 252 015 Old_age Offline - 0
9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 15895
10 Spin_Retry_Count 0x0032 252 252 051 Old_age Always - 0
11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 7
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 95
181 Program_Fail_Cnt_Total 0x0022 252 100 000 Old_age Always - 0
191 G-Sense_Error_Rate 0x0022 100 100 000 Old_age Always - 181
192 Power-Off_Retract_Count 0x0022 252 252 000 Old_age Always - 0
194 Temperature_Celsius 0x0002 064 061 000 Old_age Always - 35 (Min/Max 19/45)
195 Hardware_ECC_Recovered 0x003a 100 100 000 Old_age Always - 0
196 Reallocated_Event_Count 0x0032 252 252 000 Old_age Always - 0
197 Current_Pending_Sector 0x0032 100 100 000 Old_age Always - 1
198 Offline_Uncorrectable 0x0030 252 252 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x0036 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x002a 100 100 000 Old_age Always - 20221
223 Load_Retry_Count 0x0032 100 100 000 Old_age Always - 7
225 Load_Cycle_Count 0x0032 100 100 000 Old_age Always - 2671
SMART Error Log Version: 1
No Errors Logged
SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Extended offline Completed without error 00% 15848 -
# 2 Short offline Completed without error 00% 15815 -
# 3 Short offline Completed without error 00% 15815 -
# 4 Short offline Completed without error 00% 15813 -
# 5 Short offline Completed without error 00% 15813 -
# 6 Extended offline Completed without error 00% 15807 -
# 7 Short offline Completed without error 00% 15790 -
Re: ZFS - Directory Contents vanished
Posted: 23 Jul 2013 07:23
by b0ssman
because Reallocated_Sector_Ct is 0.
the Current_Pending_Sector 1 means one sector is having problems and is marked.
the next time this one gets read/written it es evaluated. if the operation succeeds it gets marks ok, if not it gets rellocated.
you could try reading the entire disk using dd.