Re: segfault mdadm --write-behind, 2.6.14-mm2
From: Vladimir V. Saveliev
Date: Fri Nov 18 2005 - 09:22:58 EST
Hello
Andrew Morton wrote:
> Sander <sander@xxxxxxxxxxx> wrote:
>>Neil Brown wrote (ao):
>>> If you use mdadm-2.0 and mark a device as --write-mostly, then all
>>> read requests will go to the other device(s) if possible,.
>>> e.g.
>>> mdadm --create /dev/md0 --level=1 --raid-disks=2 /dev/ramdisk \
>>> --writemostly /dev/realdisk
>>>
>>> Does this suit your needs?
>>>
>>> You can also arrange for the write to the writemostly device to be
>>> 'write-behind' so that the filesystem doesn't wait for the write to
>>> complete. This can reduce write-latency (though not increase write
>>> throughput) at a very small cost of reliability (if the RAM dies, the
>>> disk may not be 100% up-to-date).
>>With 2.6.14-mm2 (x86) and mdadm 2.1 I get a Segmentation fault when I
>>try this:
>
> It oopsed in reiser4. reiserfs-dev added to Cc...
>
>>mdadm -C /dev/md1 -l1 -n2 --bitmap=/storage/md1.bitmap /dev/loop0 \
>>--write-behind /dev/loop1
>>
>>loop0 is attached to a file on tmpfs, and loop1 is attached
>>to a file on a lvm2 volume (reiser4, if that matters).
>>
I tried ext2 on lvm2 and that did not help.
So, for now I would assume that the problem is not in reiser4 but somewhere else.
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