----- Original Message ----
> From: Dave Kempe <d...@sol1.com.au>
> To: Brett Coady <bc196...@yahoo.com.au>
> Cc: slug@slug.org.au
> Sent: Sat, 20 February, 2010 8:10:00 AM
> Subject: Re: [SLUG] RAID and LVM
>
> ----- "Brett Coady" wrote:
> >
> > These read-times were all done with: hdparm -tT /dev/(device)
> > Anyone know a good non destructive write test for benchmarking HDD ?
> >
> > Hope this helps
> > Brett
>
> Bonnie++ is what we use. You can use IOzone if you like complex charts.
> hdparm
> isn't great for this sort of thing.
The trouble with Bonnie and IOzone is that they test the filesystem , for my
example I was looking at the raw disk speed for raid results.
>
> Also, back to the one of the other suggestions - don't use RAID5. If you only
> have 3 disks, use RAID1 and 1 hotspare. They don't make disks like they used
> to,
> and RAID5 and MTBF stats meant that the chance of having a failure during a
> rebuild is too high. RAID5 is dead to me. RAID10 if you have enough disks, or
> RAID1 when you don't.
> and use LVM. It makes for growing/shrinking/chopping much easier. You can't
> shrink XFS. Be careful shrinking ext3.
>
> http://hardware.slashdot.org/hardware/08/10/21/2126252.shtml
> and don't backup to tape. Buy lots of harddrives, and expect to buy more of
> them.
>
> Dave
That's handy to know about RAID5, thanks
There are 2 other things I can suggest.
1: I use those cheap Caddies you get from the markets and noticed upon
installing 2 Hard Disk in 2 of them they vibrated as they are both
parallel.(well they are cheap and I only use them for backup)
Upon installing my 2 Disk for RAID without caddies, I staggered them so the
center axis is offset (trying to destroy some inertial cavitation here). If you
are real keen you may like to mount one of the drive upside down on the same
axis counter-acting inertial vibrations. (Going a bit too far ? see below.)
There was a RAID array with 20+ drives stacked one on top one another, and when
turned on the system tipped over due to inertia. If you use Gentoo this is
known as "Larry the Cow Tipping" and like normal "Cow Tipping" is frowned upon.
(yes, I know in the BIOS they have staggered Drive start for some systems,
Larry just tips slower).
2: I had an issue when setting up RAID that I always lost 1MB or 2 from one of
the HDD, this concerned me and every time I repartitioned and rebooted I lost
it again, the second drive was fine.?
After giving up and leaving the last 2 MB on both drives untouched to keep them
the same size I was happy. (sort of)
I have since that learnt that some Motherboard backup the BIOS to the end HDD
and have a setting to do so. My motherboard has no option for this and has dual
BIOS anyway but it still appears to do it!
Regards
Brett
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
