Topic: is RAID 5 possible?

[animal18]

Has anyone setup an SME server with RAID 5? I am looking to setup a backup server and would like to be able to install the monitering software. I would love to know if this is possible... ?

[pcworkswv]

Are you wanting to setup software RAID within Linux or do you already have a RAID card installed in your backup server?

Here is a link to RedHat regarding software RAID, which may help but I've never tried it; also not sure if it could be done with SME Server either.

http://www.redhat.com/docs/manuals/linux/RHL-7.2-Manual/custom-guide/software-raid.html

Your easiest solution would probably be to setup hardware RAID. You could probably find a used RAID card and SCSI drives from eBay for pretty cheap.

Hope this helps.

Nathan

[Reinhold]

animal18

RAID5 software sure works (it's in the kernel) on SME.
Search the forum for quite a few threads (old!).
It's even easy !  
(as long as you do not want to boot from the Raid5 array)
- and even software only you'll enjoy max speed on a
100Mbit net provided your CPU is above 1GHz ...

enjoy

Reinhold
...sending this via a 1Terabyte+Raid1+RAID5 SME

P.S.: Stay away from SATA for now!

[animal18]

Thanks for all the input. I didn't know about the software RAID...

Also, why stay away from SATA? Does SME have some issues?

I am going to go with a hardware RAID 5 solution. Specifically the Promise FastTrak S150 SX4. I just want to know if it is possible to install the RAID monitering software that Promise includes with the card.

If a dead RAID can't tell me it's dead, not much use in having one

[Reinhold]

...I'm not sure you are going to be happy with that controller

(i) search the forum, read especially: http://forums.contribs.org/index.php?topic=21493.0
...sure you have a good driver?

(ii) look at the controller specs... (it's not really hardware and imho most cpu's are faster <eg>)
also note that a raid5 capacity is (nofdrives-1)*hdcapacity so better use MANY drives !

..as to sata: the (old) SME-linux-kernel has severe problems with sata drives (mostly they will run only as non dma - better check).
 
x-fingers
Reinhold

[psc]

Why ?
There is no reason for RAID 5 !
A lot people might think, that a higher RAID-level (number) is the "better" one ... thats wrong !

If you want a fast solution use RAID-1, its the fastest (and most expensive) RAID-Level.

You can use ready to run raid cages
e.g. http://www.3ware.com/products/ata.asp
normaly the do not need any software.

Has anyone setup an SME server with RAID 5? I am looking to setup a backup server and would like to be able to install the monitering software. I would love to know if this is possible... ?

[animal18]

First off, this server is for my own amusement. I basically want data storage that can take the loss of a drive without issue. I have worked with many RAID 5 servers, so I know the limitations, and advantages.

I know the card is not fully hardware, but where else are you going to get such a cheap card? The reviews are also favorable, so we shall see. This will also be installed on a slower machine, so any help that I can get should benefit the overall speed.

Hum, the driver issue looks like it will be a pain, but I think it is workable. I'll have to play around with it. SME is not my only choice, it just seems very neat and clean, so I would love to get it to work.

I'll also have to check on the non-DMA issue. It's not a show stopper, but who knows.

From my point of view, there is no "best" RAID level, just one that fits what you would like to do. I am not looking for performance, just fault tolerence.

Plus, RAID 5 is just neato.  

Thanks for all the help so far, let me know if you think of anything else and i'll let you know how it goes.

[Reinhold]

psc,

Not everybody will be happy if they have to buy 2 harddisks and be able to just use the capacity of a single one...
especially if write performance turns out to be lower and read performance is only about 1.5x
...and (excuse my wording) YOU might want to recheck on what's "wrong" and what's BETTER
- unless of course you insist that the "rest of world is WRONG"  
Hint: Measure, use facts, not fiction!  

---

animal,

happy fiddling ... 'm afraid you'll get your share with your choice of controller <eg>
just let us know what you settled on
- especially if you move away from SME and why...

BTW: Did you know that you get RAID1 on SME "automatically"? Just connect 2 HDs and install SME ! Just "YES" to a single question does it all .-)

Reinhold

[psc]

Hi Reinhold,

"Hint: Measure, use facts, not fiction!" oh yes i do, allready a long time.
My statement "a higher RAID-level (number) is the better one ... thats wrong" is NOT a valuation of RAID Levels !

It allways depends on your needs. So animal18 is right ..." there is no "best" RAID level, just one that fits what you would like to do"

P.S. "Measure", with real good SCSI-RAID controllers and fast (expensive) SCSI-Disks, i measure (ok, ok ... on large database servers) the highest performance with RAID-1, but with another database ... ??

[jeremy]

Reinhold,

Given your comment regarding SATA, I thought you might have some ideas on the problem we're experiencing:

http://forums.contribs.org/index.php?topic=23503.0