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topics:zfs-on-linux-memory-limit [2017/03/26 04:09] (current)
orzfly created
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 +====== Limit ZFS on Linux Memory Usage ======
  
 +<code bash>
 +echo "options zfs zfs_arc_max=1073741824" >> /etc/modprobe.d/zfs.conf
 +echo 1073741824 > /sys/module/zfs/parameters/zfs_arc_max
 +update-initramfs -u
 +</code>
 +
 +1073741824 is 1 GiB. It is good to use at most 50 percent (which is the default) of the system memory for ZFS ARC to prevent performance shortage of the host. 
 +
 +===== Monitoring =====
 +arcstat.py is located in ''zfsutils-linux'' on Ubuntu.
 +
 +<code shell-session>
 +$ apt-file search arcstat.py
 +zfsutils-linux: /usr/sbin/arcstat.py
 +</code>
 +
 +<code shell-session>
 +# arcstat.py 1
 +    time  read  miss  miss%  dmis  dm%  pmis  pm%  mmis  mm%  arcsz     c
 +12:06:55              0        0        0        0  1005M  1024M
 +12:06:56    59    10     16    10   16        0        0  1005M  1024M
 +12:06:57    68    10     14    10   14        0       30  1005M  1024M
 +12:06:58    59    10     16    10   16        0        0  1005M  1024M
 +12:06:59    55         10       10        0        0  1005M  1024M
 +</code>
 +
 +<code shell-session>
 +# arcstat.py -h
 +Usage: arcstat.py [-hvx] [-f fields] [-o file] [-s string] [interval [count]]
 +
 +         -h : Print this help message
 +         -v : List all possible field headers and definitions
 +         -x : Print extended stats
 +         -f : Specify specific fields to print (see -v)
 +         -o : Redirect output to the specified file
 +         -s : Override default field separator with custom character or string
 +
 +Examples:
 +        arcstat.py -o /tmp/a.log 2 10
 +        arcstat.py -s "," -o /tmp/a.log 2 10
 +        arcstat.py -v
 +        arcstat.py -f time,hit%,dh%,ph%,mh% 1
 +</code>
 +
 +===== See Alsos =====
 +  * https://pve.proxmox.com/wiki/ZFS_on_Linux
 +  * https://www.solaris-cookbook.eu/linux/linux-ubuntu/debian-ubuntu-centos-zfs-on-linux-zfs-limit-arc-cache/
 +  * http://fibrevillage.com/storage/169-zfs-arc-on-linux-how-to-set-and-monitor-on-linux
 +
 +{{tag>zfs zfs-on-linux memory}}