Re: Problem identified: WAPL/RAIDframe performance problems

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Edgar Fu=C3=9F <[email protected]> writes:

>> I seem to be facing two problems:
>>=20
>> 1. A certain svn update command is ridicously slow on my to-be file serv=
er.
>> 2. During the svn update, the machine partially locks up and fails to re=
spond=20
>>    to NFS requests.
> Thanks to very kind help by hannken@, I now at least know what the proble=
m is.
>
> Short form: WAPBL is currently completely unusable on RAIDframe (I always=
=20
> suspected something like that), at least on non-Level 0 sets.
>
> The problem turned out to be wapbl_flush() writing non-fsbsize chunks on =
non-
> fsbsize boundaries. So RAIDframe is nearly sure to RMW.
> That makes the log being written to disc at about 1MB/s with the write lo=
ck=20
> on the log being held. So everything else on that fs tstiles on the log's=
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> read lock.

Do you see this on RAID-1 too?

I wonder if it's possible (easily) to make the log only use fsbize
boundaries, (maybe forcing it to be bigger as a side effect.)

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