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Can't get rid of INACTIVE read/write snapshot

linux-lvm Marcel Gsteiger 2 participants 3 messages Jun 2, 2008 – Jul 21, 2008

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#0 lore raw

Hi all

I'm using lvm2-2.01.08-2.1 on fc4, kernel 2.6.16-1 with linux-vserver patches.

A while ago, I mistakenly created a 39GB read-write snapshot of my /vservers partition (which, btw, seemed to work). But after some time this partition got to an overflow and since then I can't get rid of it anymore. See the lvdisplay output below.

lvchange -an or --refresh gives me a message "Can't change snapshot logical volume "vservers_snapshot"".

lvremove lets me wait, then "top" shows 100% IO-Wait but does not come to an end (at least after an hour). I don't know how much patience I would need, this box is rather fast otherwise (dual xeon 2.8GHz w/ SATA drives).

Rebooting does not help anything.

Is there a safe way to simply get rid of this snapshot? Any help would much be appreciated.

Regards
--Marcel

--- Logical volume ---

  LV Name                /dev/vg00/lv00_vservers
  VG Name                vg00
  LV UUID                9oELP3-2l7d-gTML-2xg2-unTu-znP0-qVd3Mc
  LV Write Access        read/write
  LV snapshot status     source of
                         /dev/vg00/vservers_snapshot [INACTIVE]
  LV Status              available
  # open                 1
  LV Size                39,06 GB
  Current LE             625
  Segments               1
  Allocation             contiguous
  Read ahead sectors     0
  Block device           253:9

--- Logical volume ---

  LV Name                /dev/vg00/vservers_snapshot
  VG Name                vg00
  LV UUID                cQEj3z-V2jD-QOCl-3Yea-ETQZ-Egj9-2B7nd2
  LV Write Access        read/write
  LV snapshot status     INACTIVE destination for /dev/vg00/lv00_vservers
  LV Status              available
  # open                 0
  LV Size                39,06 GB
  Current LE             625
  Segments               1
  Snapshot chunk size    4,00 KB
  Allocated to snapshot  100,00% 
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:8
#1 lore raw
Quoted 9 lines

Hi all

I'm using lvm2-2.01.08-2.1 on fc4, kernel 2.6.16-1 with linux-vserver patches.

A while ago, I mistakenly created a 39GB read-write snapshot of my /vservers partition (which, btw, seemed to work). But after some time this partition got to an overflow and since then I can't get rid of it anymore. See the lvdisplay output below.

lvchange -an or --refresh gives me a message "Can't change snapshot logical volume "vservers_snapshot"".

lvremove lets me wait, then "top" shows 100% IO-Wait but does not come to an end (at least after an hour). I don't know how much patience I would need, this box is rather fast otherwise (dual xeon 2.8GHz w/ SATA drives).

Hi

It looks like an unknown bug in lvremove. Send a strace of lvremove while it waits for that long amount of time.

Mikulas

Quoted 46 lines

Rebooting does not help anything.

Is there a safe way to simply get rid of this snapshot? Any help would much be appreciated.

Regards
--Marcel

--- Logical volume ---

 LV Name                /dev/vg00/lv00_vservers
 VG Name                vg00
 LV UUID                9oELP3-2l7d-gTML-2xg2-unTu-znP0-qVd3Mc
 LV Write Access        read/write
 LV snapshot status     source of
                        /dev/vg00/vservers_snapshot [INACTIVE]
 LV Status              available
 # open                 1
 LV Size                39,06 GB
 Current LE             625
 Segments               1
 Allocation             contiguous
 Read ahead sectors     0
 Block device           253:9

--- Logical volume ---

 LV Name                /dev/vg00/vservers_snapshot
 VG Name                vg00
 LV UUID                cQEj3z-V2jD-QOCl-3Yea-ETQZ-Egj9-2B7nd2
 LV Write Access        read/write
 LV snapshot status     INACTIVE destination for /dev/vg00/lv00_vservers
 LV Status              available
 # open                 0
 LV Size                39,06 GB
 Current LE             625
 Segments               1
 Snapshot chunk size    4,00 KB
 Allocated to snapshot  100,00%
 Allocation             inherit
 Read ahead sectors     0
 Block device           253:8

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read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

#2 lore raw

.sorry for the delay, I tried again to lvremove, find the strace enclosed.

After the output "flock(3, LOCK_EX

at the end, lvremove seems to go into an endless loop (100% CPU usage).

Then I tried the following:

kill -9 <pid of lvremove>
rm /var/lock/lvm/V_vg00

to remove /var/lock/lvm/V_vg00 "by hand" and tried again. Now the system does not go to 100% CPU usage anymore, but lvremove does not terminate. See my second lvremove2.strace.

As mentioned before, I simply wanted to get rid of a overflowed snapshot and clean up my volume group, as I should extend the LVM in question. How can I safely accomplish this in my situation?

Thanks for your help and best regards
--Marcel

Quoted 11 lines
Quoted 1 line
Quoted 1 line

Mikulas Patocka <[email protected]> 03.06.2008 21:15 >>>

Hi all

I'm using lvm2-2.01.08-2.1 on fc4, kernel 2.6.16-1 with linux-vserver patches.

A while ago, I mistakenly created a 39GB read-write snapshot of my /vservers partition (which, btw, seemed to work). But after some time this partition got to an overflow and since then I can't get rid of it anymore. See the lvdisplay output below.

Quoted 7 lines

lvchange -an or --refresh gives me a message "Can't change snapshot logical volume "vservers_snapshot"".

lvremove lets me wait, then "top" shows 100% IO-Wait but does not come to an end (at least after an hour). I don't know how much patience I would need, this box is rather fast otherwise (dual xeon 2.8GHz w/ SATA drives).

Hi

It looks like an unknown bug in lvremove. Send a strace of lvremove while it waits for that long amount of time.

Mikulas

Quoted 47 lines

Rebooting does not help anything.

Is there a safe way to simply get rid of this snapshot? Any help would much be appreciated.

Regards
--Marcel

--- Logical volume ---

 LV Name                /dev/vg00/lv00_vservers
 VG Name                vg00
 LV UUID                9oELP3-2l7d-gTML-2xg2-unTu-znP0-qVd3Mc
 LV Write Access        read/write
 LV snapshot status     source of
                        /dev/vg00/vservers_snapshot [INACTIVE]
 LV Status              available
 # open                 1
 LV Size                39,06 GB
 Current LE             625
 Segments               1
 Allocation             contiguous
 Read ahead sectors     0
 Block device           253:9

--- Logical volume ---

 LV Name                /dev/vg00/vservers_snapshot
 VG Name                vg00
 LV UUID                cQEj3z-V2jD-QOCl-3Yea-ETQZ-Egj9-2B7nd2
 LV Write Access        read/write
 LV snapshot status     INACTIVE destination for /dev/vg00/lv00_vservers
 LV Status              available
 # open                 0
 LV Size                39,06 GB
 Current LE             625
 Segments               1
 Snapshot chunk size    4,00 KB
 Allocated to snapshot  100,00%
 Allocation             inherit
 Read ahead sectors     0
 Block device           253:8

_______________________________________________
linux-lvm mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/