Date: Fri, 3 May 2024 10:03:09 -0700 From: Jim Long <freebsd-questions@umpquanet.com> To: freebsd-questions@freebsd.org Subject: Unable to limit memory consumption with vfs.zfs.arc_max Message-ID: <ZjUYzdiz01GgnbX/@sfo.umpquanet.com>
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I have a small server with 16G RAM running
stable/14-n267062-77205dbc1397.
The kernel has been consuming all the RAM, as ARC cache from what I can
see, requiring frequent (daily?) reboots to keep it functional. The ZFS pool
is not large:
# zpool list
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
gauss 3.62T 2.00T 1.63T - - 0% 55% 1.00x ONLINE -
I'm attempting to limit vfs.zfs.arc_max to 4294967296 (4G) in
/etc/sysctl:
# $FreeBSD$
#
# This file is read when going to multi-user and its contents piped thru
# ``sysctl'' to adjust kernel values. ``man 5 sysctl.conf'' for details.
#
# Uncomment this to prevent users from seeing information about processes that
# are being run under another UID.
#security.bsd.see_other_uids=0
kern.maxvnodes=1000000
vfs.zfs.arc_max=4294967296
# sysctl vfs.zfs.arc_max
vfs.zfs.arc_max: 4294967296
# top -b
last pid: 39206; load averages: 0.19, 0.22, 0.18 up 0+20:32:15 09:48:48
83 processes: 1 running, 82 sleeping
CPU: 0.1% user, 0.0% nice, 1.0% system, 0.0% interrupt, 98.9% idle
Mem: 636K Active, 72M Inact, 18M Laundry, 15G Wired, 338M Free
ARC: 14G Total, 9675M MFU, 3801M MRU, 3456K Anon, 79M Header, 279M Other
678M Compressed, 7943M Uncompressed, 11.71:1 Ratio
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
1903 root 1 21 0 144M 39M select 0 0:12 0.59% smbd
1586 root 1 20 0 33M 5400K select 1 0:57 0.00% snmpd
1812 root 1 20 0 137M 27M select 0 0:06 0.00% smbd
1956 root 1 20 0 151M 32M select 3 0:04 0.00% smbd
5779 root 1 20 0 144M 38M select 0 0:04 0.00% smbd
36017 root 1 20 0 145M 40M select 3 0:04 0.00% smbd
1572 ntpd 1 20 0 23M 1260K select 1 0:03 0.00% ntpd
1816 root 1 20 0 52M 10M select 3 0:02 0.00% winbindd
2056 root 1 20 0 24M 848K select 2 0:02 0.00% httpd
2287 root 1 20 0 24M 1272K select 0 0:02 0.00% httpd
1612 root 1 68 0 22M 2976K select 0 0:02 0.00% sshd
1787 root 1 20 0 42M 2312K select 0 0:01 0.00% nmbd
2047 65529 1 20 0 11M 1208K select 2 0:01 0.00% mathlm
1517 root 1 20 0 13M 1268K select 3 0:01 0.00% syslogd
1621 root 1 20 0 19M 1716K select 3 0:01 0.00% sendmail
1854 root 1 20 0 53M 13M select 3 0:01 0.00% winbindd
1831 root 1 20 0 19M 1796K select 3 0:01 0.00% sendmail
2031 root 1 20 0 19M 3236K select 0 0:01 0.00% sendmail
This is showing ARC at 14G, when I'm trying to limit it to 4G.
How can I enforce a limit on how much RAM the ARC cache is allowed to
consume?
Thank you!
Jim
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