zfs very poor performance compared to ufs due to lack of cache?

Andriy Gapon avg at freebsd.org
Sun Sep 12 17:06:09 UTC 2010


on 12/09/2010 19:51 Steven Hartland said the following:
> ----- Original Message ----- From: "Andriy Gapon" <avg at freebsd.org>
> 
>>>> --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
>>>> +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
>>>> @@ -500,6 +500,7 @@ again:
>>>>  sched_unpin();
>>>>  }
>>>>  VM_OBJECT_LOCK(obj);
>>>> + vm_page_set_validclean(m, off, bytes);
>>> Only if error == 0, perhaps ?
> 
> Ok tried this and still no joy, the value of the cache always falls to that of
> the min
> value and all memory used by sendfile still seems to get lost into inactive
> memory :(

Well, I do not see enough technical details in this report to see what's going
on.  As we know, there is also another issue (not sendfile specific) leading to
ARC shrinking.

-- 
Andriy Gapon


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