Topic: Raid5 on 6.03 - What's needed?

[Reinhold]

A non-profit youth organization that I support will receive a donation of 4x 80Gb IBM IDE HDs soon.
I have supplied them with (central) SME 6.03b file server incl. 2x 80Gb IDE HDs mainly for their "music and video studio" (PIII 500, 128MB RAM, Asus P3B-F board with UDMA/33 BusMasterIDE).

Now I do need a 2nd PCI IDE controller to add those new HDs.
Also one big storage area would be nice to have there.

- What controller would you buy?
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(from boardmessages it seems highpoint 370 is a bad choice...)
(...and since I'm going to be the donor it won't be a raid box

- Would you recommend setting up a software raid5 array with the above hardware?
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Note: It's mostly 4 users only but the amount of data shuffling for audio/video is large. So while "one large drive" would be desirable I wonder if under SME 6.03b a PIII 500 with only 128Mb is sufficient to pull off software raid ? How much more RAM do we need to (I buy?

Thanks for helping !

[Dan Brown]

I'd vote for a 3Ware Escalade 7500-series controller.  It's a true hardware RAID controller, and supported out of the box by SME.  All 6 drives would go on the 3Ware, giving you ~400GB in the array.  I wouldn't use software RAID for a Raid 5 array; it's too computationally intensive.

[Tom Keiser]

I fully agree with Dan Brown about the 3ware controller. You can't do better than that for IDE raid (unless you had SATA drives/controller).

I will say that the donated IBM drives are likely to give you trouble.  I used to install a lot of them, and they are dropping like flies this whole year. So, keep an eye on them -- at least they should still have some warranty left -- they were either 3 or 5 year warranted drives.

Good luck,

Tom

[Reinhold]

Thanks Dan, Thanks Tom,

Too bad a 3ware 8channel controller is at least 300$, more than buying 2 new 160Gb HDs ... so while I noticed that you, Dan, are  a happy user, this would set us back too much .-/
Tom those IBMs supposedly do have the firmware fix that moves the heads every few minutes ... but nevertheless I do share those fears...

Can't I just buy a PROMISE FAST TRACK
(like installed into RH 7.3 at http://www.murty.net/ataraid/) ?

Thanks for any hint to a cheap solution...!!!


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Maybe this should be a new topic but:
Dan: http://www.sr5tech.com/performance.htm basically says that with a 1.8Ghz CPU "LinuxSoftware-Raid5" is  faster than 3ware ???
Great review: in comparision 3ware is excellent http://www.xbitlabs.com/articles/storage/display/3ware-7810.html

[Tom Keiser]

Reinhold wrote:

> Can't I just buy a PROMISE FAST TRACK
> (like installed into RH 7.3 at

Reinhold:  Unless Promise has changed, their drivers are not in the kernel, and they offer only binary drivers for certain distro versions, not the source code. So, there's no way to make Promise work in SME unless their drivers are now included in SME 6.


> Dan: http://www.sr5tech.com/performance.htm basically says
> that with a 1.8Ghz CPU "LinuxSoftware-Raid5" is  faster than
> 3ware ???

He tested the 7500 which has been replaced by the 7506, which is supposed to be 25% faster on raid 5. Also, the setup and maintenance of software RAID5 is do-able, but not simple. There's an entire book on the subject (which I must have loaned out, or I'd give you the reference).

> Great review: in comparision 3ware is excellent
> http://www.xbitlabs.com/articles/storage/display/3ware-7810.html

I don't recognize the 7810 -- it's not a current product that I'm aware of, so I can't comment on the review.

Good Luck,

Tom

[Reinhold]

Tom,

Thanks for your valuable comments.
Guess I'm in a catch2+4 situation here .-)

I've searched up&down and unlike the highpoint stuff, people seem to get the promise controllers working.

So assuming I'll get a promise working  as a standard IDE controller, in 6.03
and the kernel supposedly does support at least two standard controllers,
I took the plunge, went ahead and ordered a Promise Ultra TX2 for just 20 bucks .-)
(it's the none raid stuff)

(1) I will then try to set up 6 separate HDs first
 - if that works I should have a base to play from.

(2) Afterwards I'll spent 2 evenings fiddling to "raid them" - ignoring if it fails.
My short course will be:
- (new IBM disks are partitioned and formated in 1)
- create /etc/raidtab
---------------------------
 raiddev /dev/md0
 raid-level 5
 nr-raid-disks 4
 nr-spare-disks 0
 parity-algorithm left-symmetric
 chunk-size 64
 device /dev/hde1
 raid-disk 0
 device /dev/hdf1
 raid-disk 1
 device /dev/hdg1
 raid-disk 2
 device /dev/hdh1
 raid-disk 3
---------------------------
- mkraid /dev/md0
- raidstart /dev/md0

... or am I fundamentally mistaken ???
and thus have to give up and settle with 6 separate drives (and maybe symlinks).

Thanks