Francois Dion francois.dion at gmail.com
Wed Dec 6 12:01:25 CST 2006

On 12/6/06, Mike <xa87n at yahoo.com> wrote:
> --- Francois Dion <francois.dion at gmail.com> wrote:
> > On 12/6/06, Mike <xa87n at yahoo.com> wrote:
> > > > If you're simply wanting to get experience of RAID5 and aren't
> > *too*
> > > > bothered about performance there are probably some
> > > > older systems available on the internet, though depending on the
> > age
> > > > of the system you may be looking at 36Gb disks so
> > > > you'd want 7 or 8 of those in a desktop multipack or similar.
> > >
> > > Performance is not critically important, mostly I need to have a
> > couple
> > > of hundred GB available. So older systems are OK, with either
> > built-in
> > > or extra PCI RAID host adapter.
> > >
> > > Mostly, it should be no more than few thousand $$, sparc, and
> > without
> > > external storage. Older hardware is fine.
> >
> > How much rack space do you have? Anyway, back to V240, yes it takes 4
> > drives, 146GB max each if under sun support but there are ways to go
> > higher. You mention that performance is not critically important, but
> > max space is. Does it need to be redundant?
> A couple of U, maybe 3. Unofficial is fine. It has to be redundant, it
> will run some sort of a database, I don't know which one.

You can use: http://www.pc-pitstop.com/scsi_ide_adapters/aec7730.asp

Altough I've used this on other Sun hardware, I've not tried it
specifically on a V240. Note that it does U160 only. But you can put
500GB sata drives in. You'll also need to add a 68 to 80 pin adapter
(about $10). We have some V240 but they are in production so I cant
test that. I know some list members have tried this, maybe somebody is
using this on a V240.

> > You could also add something like an ST-D130 adding 3 more drives in
> > 1U (i know you said no external, but you might want to consider a 1U
> > solution).
> Yes, thanks, definitely will consider this one.
> >
> > Why hardware raid, also? What are you going to run on this? zfs
> > zraid1
> > with compression is really nice on those v240. BTW, sol 10 u4 will
> > let
> > you configure zraid1 including boot disk (supported by sun - you can
> > actually do this on x86 hardware with solaris 10 u3 or solaris nevada
> > but it is unsupported). zfs compression has given me a serious
> > performance boost, except with oracle database, but that's because I
> > didn't match the zfs settings to the database and didn't have time to
> > play with this.
> Well, its been a while since I used anything but VRTS (out of question
> because of licensing costs), so without giving it a lot of serious
> thought, it was simpler to just use hardware raid.

put the drives in, devfsadm so they show up as c1t2d0, c1t3d0, c1t4d0 then:
zpool create mybigspace raidz c1t2d0 c1t3d0 c1t4d0
you are done. Hard to be simpler than that.
To create a filesystem on your pool:
zfs create mybigspace/u01

zfs set compression=on mybigspace/u01

You can combine both above commands in 1. You can also set a different
mount point, set quotas, reservations, no access time (improves
performance), set snapshots, rollback etc. All with 1 line commands.
It's trivial to use, free and comes with Solaris 10.

> The second note is
> performance, although performance is not critical, avoiding any
> slowdowns is always welcome.

Raid5 is already a performance hit.

> But if software raid is decent now, that
> is fine and could work out.
> So if zraid or SVM is something to consider (and SVM comes with
> Sol10?), then great. Can zfs do raid5?

It's actually a better raid 5, it's raidz.

> Are they solid, in case the
> server crashes, does it recover fine?

It uses copy on write. You can pull the plug at any time, it'll always
come back up, unlike most everything else under the sun (no pun
intended, really. Including hardware raid - we've had many issues with
hardware raid-5 over the years - you still need UFS - altough UFS with
logging is a lot better than it used to be).

I'm going to be running some tests on my E5500 with postgresql soon,
i'm waiting on some new scsi terminators, they should have been here
weeks ago. I would be able to provide benchmarks then. Look at iozone
too to tune your system and benchmark stuff in general. Do you know
how many transactions per second you'll be required to do? Homegrown
app on top of the database or canned app?


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