Date: Mon, 21 Oct 2013 09:26:14 +0100 From: "Steven Hartland" <killing@multiplay.co.uk> To: "Vitalij Satanivskij" <satan@ukr.net> Cc: Vitalij Satanivskij <satan@ukr.net>, "Justin T. Gibbs" <gibbs@FreeBSD.org>, freebsd-current@freebsd.org, Borja Marcos <borjam@sarenet.es>, Dmitriy Makarov <supportme@ukr.net> Subject: Re: ZFS secondarycache on SSD problem on r255173 Message-ID: <6917E0AC86C444EFB3B55750175BADED@multiplay.co.uk> References: <E5E6AB7C-C067-4B92-8A38-9DD811011D6F@FreeBSD.org> <7059AA6DCC0D46B8B1D33FC883C31643@multiplay.co.uk> <20131017061248.GA15980@hell.ukr.net> <326B470C65A04BC4BC83E118185B935F@multiplay.co.uk> <20131017073925.GA34958@hell.ukr.net> <2AFE1CBD9B124E3AB9E05A4E483CCE03@multiplay.co.uk> <20131018080148.GA75226@hell.ukr.net> <256B2E5A0BA44DCBB45BB3F3E820E190@multiplay.co.uk> <20131018144524.GA30018@hell.ukr.net> <4459A6FAB7B8445C97CCB9EFF34FD4F0@multiplay.co.uk> <20131019085547.GA33582@hell.ukr.net>
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Hows things looking Vitalij?
----- Original Message -----
From: "Vitalij Satanivskij" <satan@ukr.net>
> Ok. Just right now system rebooted with you patch.
>
> Trim enabled again.
>
> WIll wait some time untile size of used cache grow's.
>
>
> Steven Hartland wrote:
> SH> Looking at the l2arc compression code I believe that metadata is always
> SH> compressed with lz4, even if compression is off on all datasets.
> SH>
> SH> This is backed up by what I'm seeing on my system here as it shows a
> SH> non-zero l2_compress_successes value even though I'm not using
> SH> compression at all.
> SH>
> SH> I think we we may well need the following patch to set the minblock
> SH> size based on the vdev ashift and not SPA_MINBLOCKSIZE.
> SH>
> SH> svn diff -x -p sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
> SH> Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
> SH> ===================================================================
> SH> --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c (revision 256554)
> SH> +++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c (working copy)
> SH> @@ -5147,7 +5147,7 @@ l2arc_compress_buf(l2arc_buf_hdr_t *l2hdr)
> SH> len = l2hdr->b_asize;
> SH> cdata = zio_data_buf_alloc(len);
> SH> csize = zio_compress_data(ZIO_COMPRESS_LZ4, l2hdr->b_tmp_cdata,
> SH> - cdata, l2hdr->b_asize, (size_t)SPA_MINBLOCKSIZE);
> SH> + cdata, l2hdr->b_asize, (size_t)(1ULL << l2hdr->b_dev->l2ad_vdev->vdev_ashift));
> SH>
> SH> if (csize == 0) {
> SH> /* zero block, indicate that there's nothing to write */
> SH>
> SH> Could you try this patch on your system Vitalij see if it has any effect
> SH> on the number of l2_cksum_bad / l2_io_error?
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