Re: ZFS L2ARC - incorrect size and abnormal system load on r255173

If you are still seeing high load try commenting out the following
which should disable l2arc compression.
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
        if (l2arc_compress)
                hdr->b_flags |= ARC_L2COMPRESS;

    Regards
    Steve
----- Original Message ----- 
From: "Vitalij Satanivskij" <satan_at_ukr.net>
To: "Steven Hartland" <killing_at_multiplay.co.uk>
Cc: "Vitalij Satanivskij" <satan_at_ukr.net>; "Allan Jude" <freebsd_at_allanjude.com>; "Dmitriy Makarov" <supportme_at_ukr.net>; 
<freebsd-current_at_freebsd.org>
Sent: Tuesday, October 22, 2013 3:10 PM
Subject: Re: ZFS L2ARC - incorrect size and abnormal system load on r255173


>
> First of all Thank you for help.
>
> As for high load on system, looks like problems with l2arc have litle impact on load comparatively to another just now
>
> not fully classifed things.
>
> Looks like ower internal software and libs that it use didn't like new VMEM subsystem, at last
> system behavior complitely diferent from 6 month older CURRENT.
>
> So for now none problem's with l2arc errors.
>
> Will try to understand reason of load and fix or at last ask for help again ^).
>
>
>
>
> Steven Hartland wrote:
> SH> First off I just wanted to clarify that you don't need to compression on
> SH> dataset for L2ARC to use LZ4 compression, it does this by default as is
> SH> not currently configurable.
> SH>
> SH> Next up I believe we've found the cause of this high load and I've just
> SH> committed the fix to head:
> SH> http://svnweb.freebsd.org/base?view=revision&sortby=file&revision=256889
> SH>
> SH> Thanks to Vitalij for testing :)
> SH>
> SH> Dmitriy if you could test on your side too that would be appreciated.
> SH>
> SH>     Regards
> SH>     Steve
> SH>
> SH> ----- Original Message ----- 
> SH> From: "Vitalij Satanivskij" <satan_at_ukr.net>
> SH> To: "Allan Jude" <freebsd_at_allanjude.com>
> SH> Cc: <freebsd-current_at_freebsd.org>
> SH> Sent: Thursday, October 10, 2013 6:03 PM
> SH> Subject: Re: ZFS L2ARC - incorrect size and abnormal system load on r255173
> SH>
> SH>
> SH> > AJ> Some background on L2ARC compression for you:
> SH> > AJ>
> SH> > AJ> http://wiki.illumos.org/display/illumos/L2ARC+Compression
> SH> >
> SH> > I'm alredy see it.
> SH> >
> SH> >
> SH> >
> SH> > AJ> http://svnweb.freebsd.org/base?view=revision&revision=251478
> SH> > AJ>
> SH> > AJ> Are you sure that compression on pool/zfs is off? it would normally
> SH> > AJ> inherit from the parent, so double check with: zfs get compression pool/zfs
> SH> >
> SH> > Yes, compression turned off on pool/zfs, it's was may time rechecked.
> SH> >
> SH> >
> SH> >
> SH> > AJ> Is the data on pool/zfs related to the data on the root pool? if
> SH> > AJ> pool/zfs were a clone, and the data is actually used in both places, the
> SH> > AJ> newer 'single copy ARC' feature may come in to play:
> SH> > AJ> https://www.illumos.org/issues/3145
> SH> >
> SH> > No, both pool and pool/zfs have diferent type of data, pool/zfs was created as new empty zfs (zfs create pool/zfs)
> SH> >
> SH> > and data was writed to it from another server.
> SH> >
> SH> >
> SH> > Right now one machine work fine with l2arc. This machine without patch for corecting ashift on cache devices.
> SH> >
> SH> > At last 3 day's working with zero errors. Another servers with same config similar data, load and so on after 2 day
> SH> > work began report abouy errors.
> SH> >
> SH> >
> SH> > AJ>
> SH> > AJ>
> SH> > AJ>
> SH> > AJ> -- 
> SH> > AJ> Allan Jude
> SH> > AJ>
> SH> > AJ> _______________________________________________
> SH> > AJ> freebsd-current_at_freebsd.org mailing list
> SH> > AJ> http://lists.freebsd.org/mailman/listinfo/freebsd-current
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> SH> > _______________________________________________
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> SH> >
> SH>
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