[zfs-discuss] Seeking ZFS, ZIL, and L2ARC configuration comments

Christ Schlacta aarcane at aarcane.org
Thu Dec 15 02:18:16 EST 2011


The cache/root system seems fine, If a bit overkill. You won't get much gain from that much cache unless you're using dedup and probably not even then. If you can afford another ssd then a better investment might be a third 2tb to use in raid-z. Double your usable space. A better option than rsync might be Amanda or baccula, both of which are enterprise grade backup solutions designed for exactly what you want to do. Or quite close at least. Look into them. 

I keep home on zfs and export it via nfs and samba, performance is acceptable for pretty much everything. If you log in directly you may notice a difference, but I seldom do.

Also, you should consider running your database on zfs. For most home workloads current performance numbers should be sufficient

Omen Wild <omen.wild at gmail.com> wrote:

>I am in the process of putting together a new home server. Disk cost
>being what it is I had to really scale back my original plans. I have two
>2TB disks and an Intel 250GB SSD. The server will have a Xeon with 16GB
>of ECC RAM running Debian/unstable. It runs as a pretty light duty
>media server, email server, web server, and database server.
>
>Since it is just a small home server I don't expect to get much
>acceleration out of an external ZIL, but was thinking of dedicating 4 or
>8 GB to it. I was thinking of 60GB or so for the L2ARC, and the rest for
>the root drive. The 2TB drives will be run mirrored.
>
>I'm not quite adventurous enough to go with ZFS root, so I am planning to
>rsync or lsyncd / onto ZFS. Since I really care about my home directory I
>was thinking of setting copies=2 for that filesystem (which gives 4
>copies) which is massive overkill, but the contents are pretty small. The
>bulk directories and downloads folders would get separate filesystems
>with more relaxed settings.
>
>Questions:
>
>Is the ZIL worth it at all given that all my (small) databases will
>reside on the SSD? 
>
>How much L2ARC should I use, if any? 
>
>Would it make more sense (speed wise) to have /home on the SSD and lsyncd
>the contents to ZFS?
>
>Should I go the extra mile and use ZFS root and dedicate most of the SSD
>to L2ARC?
>
>Or hold this SSD for another machine and buy a much smaller one for the
>L2ARC?
>
>Thanks,
>   Omen
>
>-- 
>The steady state of disks is full.


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