zdb doesn’t recognize my pool?

Question

On my freenas server, zpool status tells me I have 2 zfs pool : data & freenas-boot :

% zpool status
  pool: data
 state: ONLINE
  scan: scrub repaired 0 in 0 days 04:16:16 with 0 errors on Mon Nov 20 00:59:24 2017
config:

        NAME                                            STATE     READ WRITE CKSUM
        data                                            ONLINE       0     0     0
          raidz1-0                                      ONLINE       0     0     0
            gptid/3e08fdba-4564-11e7-bdef-00fd45fc38ec  ONLINE       0     0     0
            gptid/3eba62c2-4564-11e7-bdef-00fd45fc38ec  ONLINE       0     0     0
            gptid/3f704246-4564-11e7-bdef-00fd45fc38ec  ONLINE       0     0     0
            gptid/40249d11-4564-11e7-bdef-00fd45fc38ec  ONLINE       0     0     0

errors: No known data errors

  pool: freenas-boot
 state: ONLINE
  scan: scrub repaired 0 in 0 days 00:00:13 with 0 errors on Sun Mar  4 03:45:14 2018
config:

        NAME        STATE     READ WRITE CKSUM
        freenas-boot  ONLINE       0     0     0
          ada0p2    ONLINE       0     0     0

errors: No known data errors

I would like to get statistics about my data zpool but zdb gives me an error :

% sudo zdb -b data
zdb: can't open 'data': No such file or directory

But it works on the freenas-boot pool :

% sudo zdb -b freenas-boot                                                                              

Traversing all blocks to verify nothing leaked ...

loading space map for vdev 0 of 1, metaslab 55 of 119 ...
2.56G completed ( 881MB/s) estimated time remaining: 0hr 00min 00sec        
        No leaks (block sum matches space maps exactly)

        bp count:          281124
        ganged count:           0
        bp logical:    5928553472      avg:  21088
        bp physical:   2636954624      avg:   9380     compression:   2.25
        bp allocated:  3376803840      avg:  12011     compression:   1.76
        bp deduped:             0    ref>1:      0   deduplication:   1.00
        SPA allocated: 3376803840     used:  2.64%
        Dittoed blocks on same vdev: 50961

What am I doing wrong ?

Any chance you have imported that pool with `readonly=on`? There seems to be a bug around that and you can come around this with the `-e` flag with `zdb`, treating that pool as if it was exported. — Thomas, Mar 03 '18 at 15:32
No. The `data` pool was the one I created for storing my data and it’s read & write. — paulgreg, Mar 03 '18 at 16:10
Okay, but does it change anything if you use `zdb -e -b data`? — Thomas, Mar 03 '18 at 18:14
I’ve updated the question to add zpool status command result. — paulgreg, Mar 07 '18 at 07:05

score 7 · Answer 1 · edited Mar 30 '19 at 06:09

7

For whatever reason, the cache path is different on FreeNAS. They haven't patched zdb to know where to look by default.

Add -U /data/zfs/zpool.cache <POOLNAME> to all uses of zdb to get it to work.

For your example, the command would be: zdb -U /data/zfs/zpool.cache -b data

edited Mar 30 '19 at 06:09

Brandon McClure

103
3

answered Dec 15 '18 at 20:16

ohmantics

168
1
4

2

This solved my problem. Searching the freeNas bugs list I found [this bug](https://redmine.ixsystems.com/issues/14536) that was closed in 2016. – Brandon McClure Mar 30 '19 at 01:32

score 2 · Answer 2 · answered Oct 21 '18 at 09:46

I had this problem on OmniOS where zdb couldn't open my rpool. The problem was caused by guid mismatch in zfs metadata versus actual guids of my disks. I guess this is a result of replacing broken hardware and shuffling disks between zpools...

The solution was to zfs detach one device of the mirror and zfs attach it back.

zdb doesn’t recognize my pool?

2 Answers2