Hello,
I have some basic questions.
I'm using GFS with the following configuration.
node1 node2 node3 (FC3)
GFS GFS GFS
LV LV LV <-- CLVM
GNBD GNBD GNBD <-- gnbd_import -n
| | |
+------+------+
|
GNBD <-- gnbd_serv -n / gnbd_export -c
node0 (file server: FC3)
Only for snapshot and backup, CLVM has been introduced here.
Is a setup such as this correct?
If so (or not :), why "sometimes" the following error occor?
Don't I need freeze/unfreeze GFS manually, like XFS?
(on any node of node1-3)
# gfs_tool freeze /mnt/gfs
# lvcreate -s -n lv0ss0 -L 2G /dev/vg0/lv0
Logical volume "lv0ss0" created
# gfs_tool unfreeze /mnt/gfs
# mount -t gfs -o ro,lockproto=lock_nolock /dev/vg0/lv0ss0 /mnt/gfs-ss
mount: cannot mount block device /dev/vg0/lv0ss0 read-only
But if once I did gfs_fsck, the read-only mount succeeds.
Should I always do gfs_fsck before to use a snapshot?
# gfs_fsck /dev/vg0/lv0ss0
Initializing fsck
Starting pass1
Pass1 complete
--snip--
Starting pass5
Pass5 complete
# mount -t gfs -o ro,lockproto=lock_nolock /dev/vg0/lv0ss0 /mnt/gfs-ss
But on rare occasions, gfs_fsck also cause some errors.
For example,
# gfs_fsck /dev/vg0/lv0ss0
Initializing fsck
Buffer #1736310 (1 of 4) is neither GFS_METATYPE_RB nor GFS_METATYPE_RG.
Resource group is corrupted.
Unable to read in rgrp descriptor.
Unable to fill in resource group information.
The origin and snapshot LVs are as follows.
# lvdisplay
--- Logical volume ---
LV Name /dev/vg0/lv0
VG Name vg0
LV UUID fVPY4J-cndk-YD5n-wU0m-QR0S-2txI-LvnnQ5
LV Write Access read/write
LV snapshot status source of
/dev/vg0/lv0ss0 [active]
LV Status available
# open 1
LV Size 20.00 GB
Current LE 10240
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:0
--- Logical volume ---
LV Name /dev/vg0/lv0ss0
VG Name vg0
LV UUID hZea21-flge-bI5J-gcCy-pKug-0YHN-ZXR7I4
LV Write Access read/write
LV snapshot status active destination for /dev/vg0/lv0
LV Status available
# open 1
LV Size 20.00 GB
Current LE 10240
COW-table size 2.00 GB
COW-table LE 1024
Allocated to snapshot 2.35%
Snapshot chunk size 8.00 KB
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:4
[Version info]
Linux: 2.6.11-1.14_FC3smp
GFS/Cluster: CVS head of about 08 April (with CMAN/DLM)
Dev-Mapper: 1.01.01 / CVS head of about 03 May
LVM2: 2.2.01.09 / 2.2.01.10
(--disable-selinux --with-clvmd=cman --with-cluster=shared)
Thanks, and sorry for my broken English.
-- Kenji
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