Holger,
On Thu, 27 Apr 2000, Holger Kiehl wrote:
> On Thu, 27 Apr 2000, Corin Hartland-Swann wrote:
> > I was hoping that RAID-1 would 'stripe' reads between the disks,
> > increasing read performance to RAID-0 levels, but leaving write
> > performance at single-disk levels. Does anyone know why it doesn't do
> > this?
>
> I think there is a patch for this, search the archive of this list.
Thanks - where can I find the archive?
Also - is it a pretty stable patch? (This is a production server)
> > If RAID-1 doesn't 'stripe' the reads, then it seems that my best bet is
> > going for RAID-5 over 4 disks. Does anyone have any comments and/or
> > suggestions about doing this?
>
> It depends on what you want to do with /. Since /var/log is also
> located here and if you have big log files, I would make this also
> a raid 5 partition. ftpd and httpd are doing lots of small writes
> here, so raid1 will slow you down if its being used as a web or ftp
> server.
Can RAID-1 _ever_ be slower than RAID-5? Isn't it much simpler to write
out data to 2 disks at identical offsets etc, rather than spread over
various disks, plus parity calculations?
> Regardless of the raid level you choose, take a look at the man pages
> of syslog.conf. Many distributions still sync every single write to
> messages, warn, etc. If you prefix the logfiles with a minus "-"
> syslogd will NOT sync the file for every entry. I have seen many
> systems misconfigured in this way and after putting in the minus
> they where much faster and responsive.
Thanks for the pointer - I'll look into this once I've got the RAID
sussed.
Regards,
Corin
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