Topic: Spanning / Joining Disks (4x160gb)

[Mogi1]

Hello,

I want to set up an SME server 5.6 to serve storage space for a Mac OS X network.
The users'  files are typically large, min 1 gig, so I was considering using 4 160gb disks and getting them to look like one BIG 640gb space for the network. Reading a few posts on the forums though, I get the impression that this can't be done. We have 40 users and would want to give them a minimum of 5gb each using the ibays and user quota's.

I need to know if the above is possible using sme server, if so the some directions would be appreciated.

I'm new at this, please be patient with me.

Thank you,

M1K

[Steve Bush]

You could use a SCSI RAID card and set them up as RAID0.
Better yet purchase and extra hard drive and have it setup as RAID5 for redundency.

If you want to stick with an IDE solution, you may be able to get an IDE RAID card to work.
I've never used one, so I can't say how well it would work.

Here is a link I found explaining it:

http://www.tech-report.com/reviews/2002q4/ideraid/index.x?pg=1

[Kelvin]

I suggest taking a look at 3Ware's IDE RAID controllers. They are supported out of the box with SME. They have 2, 4 and 8 channel cards to choose from. One of them should do the job for you.

Kelvin

[Mogi1]

Excellent, the M/B has a Promise IDE RAID Function on board, however Linux reports this as an unknown ide controller. the Raid function does have it's own bios so its should be transparent to the OS. thanks for the help Guys, really appreciate it...

[Mogi1]

Promis has a driver for SUSE 7.3 and 8.x. Can this be used with SME server (which as far as I know is Red Hat Based)?

[Peter]

We have used 2Ware out of the box we have never been able to get the onboard raid (Promis) to work

Peter

[Boris]

The easiest way may be Accusys 7630 http://www.accusys.com.tw/prod.htm

OS independant RAID subsystem, doesn't need drivers etc...

[Jeff P]

Another approach is to use Logical Volume Management (LVM)

I was successful in setting up two 80 gig tries with one 160 gig drive to look like (or span)  as one large drive on my SME box.

Check "LVM" in this forum for some of the posts I've made prior.

Unfortunately, I created mine several months ago and no longer remember how I did except to say it has run fabulously ever since with no problems at all.

Only drawback is if a drive fails, the data is probably toast. The pros is that I didn't need to purchase expensive raid cards to accomplish the same results you seek.

SME ver 6b and 6 have the necessary kernel support for LVM.

There is plenty of howto's on the web also.

Good luck.

[Jeff P]

Try

 http://www.linux.org/docs/ldp/howto/LVM-HOWTO/
 http://www.sistina.com/lvm

Note, it might seem daunting a task to setup LVM but compare a few other sites howto's and you'll ge a feel for what to do.

[Larry Griffiths]

I agree! I used a 3Ware Escalade RAID card and 4x120GB Maxtor drives as RAID0. - I should have used RAID10, but I didn't have a spare drive and I needed the space.

SME 6Beta went straight on and I had 445GB usable.

[Kelvin]

Hi Mogi1,

>the Raid function does have it's own bios so its should be transparent to the OS

That's incorrect. You still need a driver in order to get the RAID functions to work. If you search these forums for "Highpoint", there is a lot of info about the problems with working with cards that are not supported out of the box with SME. Promise has never released their driver source code and thus so far, I have not come across anyone who has managed to get a working driver for SME because SME does not use the normal kernel you get from the download versions of RedHat distros (drivers are kernel version dependent).

The Accusys subsystems are excellent choices except for the following :-
1. The 7500 series are RAID-1 (mirroring) systems which limit you to the capacity of the single drives
2. The 7630 can do RAID 0 which can give you the combined capacities of 3 drives but without any fauly tolerance (and in fact increases your chances of data loss as the loss of ANY of the 3 drives results in the loss of data from the entire set). The 7630's RAID 5 gives you fault tolerance but you lose approx. 30% of the combined capacity of the 3 drives AND you only get the performance from a single channel instead of one channel per hard disk if you use RAID cards like the 3Ware.

If you don't mind having to rebuild your drive sets in the event of a drive failure from backups (you are planning on backups, aren't you ??) , then go with drive spanning or RAID-0. Otherwise, RAID (1 or 5 or even 1+0) would be the way to go.

Kelvin