Re: VFS sysctl tuning

On 8/12/06, Robert Watson <rwatson@xxxxxxxxxxx> wrote:
On Sat, 12 Aug 2006, Nikolas Britton wrote:

> After reading man tuning it said to change vfs.hirunningspace to a larger
> value. What should I set it to?
>
> My RAID controller, an Areca ARC-1220, has a 256MB cache and each disk has
> 16MB of cache.
>
> What other vfs.* sysctls can I change?

The default settings are "reasonable" for many common workloads. Further
tuning generally should be done in the context of a specific workload, since
tuning generally means trading off one type of performance or functionality
for another. Only by knowing the workload can we talk about how to trade off
what you need, and what you don't.


Thanks Robert. It's a general purpose server but It's primary duty is
serving files via Samba / NFS over GigE to workstations that are
faster then it. We are typically working with hundreds of (new) ~16MB
files on any given day. It currently has a single dual-core Xeon 5030
and 1GB of system ram. I plan on upgrading it to dual dual-core Xeon
51xx and maxing out the ram if FreeBSD ever gets Xen dom0 support so
we can consolidate server equipment... Anyhow... I decided to script
out the task of finding the right setting for the hirunningspace
sysctl:

#!/bin/csh
sysctl vfs.hirunningspace=1048576
iozone -a -g 1g -b ~/arc1220_18.xls
sysctl vfs.hirunningspace=2097152
iozone -a -g 1g -b ~/arc1220_19.xls
sysctl vfs.hirunningspace=4194304
iozone -a -g 1g -b ~/arc1220_20.xls
sysctl vfs.hirunningspace=8388608
iozone -a -g 1g -b ~/arc1220_21.xls
sysctl vfs.hirunningspace=16777216
iozone -a -g 1g -b ~/arc1220_22.xls
sysctl vfs.hirunningspace=33554432
iozone -a -g 1g -b ~/arc1220_23.xls
sysctl vfs.hirunningspace=67108864
iozone -a -g 1g -b ~/arc1220_24.xls
sysctl vfs.hirunningspace=134217728
iozone -a -g 1g -b ~/arc1220_25.xls
sysctl vfs.hirunningspace=268435456
iozone -a -g 1g -b ~/arc1220_26.xls


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