From: Maurice Hilarius <maurice@harddata.com>
To: Neil Brown <neilb@cse.unsw.edu.au>
Cc: linux-raid@vger.kernel.org
Subject: Re: Software Raid Cache
Date: Sun, 23 Feb 2003 23:12:45 -0700 [thread overview]
Message-ID: <5.1.1.6.2.20030223231035.0686d400@mail.harddata.com> (raw)
In-Reply-To: <15961.46603.166633.265132@notabene.cse.unsw.edu.au>
With regards to your message at 11:04 PM 2/23/03, Neil Brown. Where you stated:
> > If this is even something doable (tweakable) Im wondering what the perf
> > gain from allocating say 2 or 4gb just to raid cache would be.
> >
> > Comments ?
>
>How do you imagine this extra 'cache' would be used.
>
>Cache on raid cards tends to be battery backed (I believe) and to
>operate as a write-behind cache thereby increasing performance. As
>main system memory is not battery backed, you cannot use it as a
>write-behind cache.
>
>NeilBrown
True, and the cache on a RAID controller is not clobbered when the OS or
computer crashes.
Mind you the same problem exists to some degree with PCI based RAID
controllers, so the most robust are host independent SCSI/SCSI RAID
controllers.
Too bad these cost about as much as a typical server!
With our best regards,
Maurice W. Hilarius Telephone: 01-780-456-9771
Hard Data Ltd. FAX: 01-780-456-9772
11060 - 166 Avenue mailto:maurice@harddata.com
Edmonton, AB, Canada http://www.harddata.com/
T5X 1Y3
prev parent reply other threads:[~2003-02-24 6:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <message from SoulBlazer on Friday February 21>
2003-02-21 20:50 ` Software Raid Cache SoulBlazer
2003-02-24 6:04 ` Neil Brown
2003-02-24 6:12 ` Maurice Hilarius [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5.1.1.6.2.20030223231035.0686d400@mail.harddata.com \
--to=maurice@harddata.com \
--cc=linux-raid@vger.kernel.org \
--cc=neilb@cse.unsw.edu.au \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).