Questions regarding journal replay
Ralf Hildebrandt
Ralf.Hildebrandt at charite.de
Wed Feb 25 17:40:38 UTC 2009
* Eric Sandeen <sandeen at redhat.com>:
> >> It'd be better to get to the bottom of the problem ... maybe iostat
> >> while it's happening to see if IO is actually happening; run blktrace to
> >> see where IO is going, do a few sysrq-t's to see where threads are at, etc.
> >
> > We had 24GB of reading from the journal device (or 12GB if it's
> > 512byte blocks). I wonder why?
>
> 24GB of reading from the journal device (during that 800s of replay
> during mount?), and your journal is 128M ... well that's odd.
After my initial report I removed the journal and created an external
journal on a 32GB partition. Hoping it would be faster, since
accoriding to the docs. the journal size is limited to 128MB.
> You say journal device; is this an external journal? I didn't think so
> from your first email, but is it?
It is now.
# dumpe2fs -h /dev/cciss/c0d0p6
dumpe2fs 1.41.3 (12-Oct-2008)
Filesystem volume name: journal_device
Last mounted on: <not available>
Filesystem UUID: 1a7063f5-8965-40f2-9feb-e37d6ac467e9
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: journal_dev
Default mount options: (none)
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 0
Block count: 8488436
Reserved block count: 0
Free blocks: 0
Free inodes: 0
First block: 0
Block size: 4096
Fragment size: 4096
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 0
Inode blocks per group: 0
Filesystem created: Thu Feb 5 14:05:36 2009
Last mount time: n/a
Last write time: Thu Feb 5 14:15:26 2009
Mount count: 0
Maximum mount count: 30
Last checked: Thu Feb 5 14:05:36 2009
Check interval: 15552000 (6 months)
Next check after: Tue Aug 4 15:05:36 2009
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Default directory hash: half_md4
Directory Hash Seed: fddb247a-97df-4582-bfcd-816ef8c17ab2
Journal block size: 4096
Journal length: 8488436
Journal first block: 2
Journal sequence: 0x0027c611
Journal start: 2
Journal number of users: 1
Journal users: 032613d3-6035-4872-bc0a-11db92feec5e
--
Ralf Hildebrandt Ralf.Hildebrandt at charite.de
Charite - Universitätsmedizin Berlin Tel. +49 (0)30-450 570-155
Geschäftsbereich IT | Abt. Netzwerk Fax. +49 (0)30-450 570-962
Hindenburgdamm 30 | 12200 Berlin
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