[wasserkool]

I have a delimma here. An 8 port Areca card cost around $500. For less money, I can get an good mobo + AMD X2 3800 for my file server.

Now if I get an fast CPU but a non-hardware RAID 5 card, will I still get good performance or is it that the IO processor on the RAID card will outperform the fastest CPU?

[RyanH]

Depends on things such as the OS that you're using. Areca's cards are very nice. If you want to do away with RAID-5 and you have 3 disks, you could get a lower speced card, add a hard drive (so you have a total of 4 hard drives) and then do a RAID 10 on them (which doesn't require a lot of computation).

[Trinary]

Here's a second vote for RAID 1+0 over RAID 5.

RAID 5 is fine for maximizing your storage space, but for small volumes (6 or 8 drives), the cost of extra drives to run in RAID 1+0 usually cost less than a decent RAID 5 card, and the RAID 1+0 normally has higher performance.

[Dans0n]

yep - at our DC most people love raid 10 but we had to use raid 5 because there are limits to 4 disks per machine and we needed as much space as possible.

Daniel

[Atamido]

If you're using RAID 1+0, you really really don't want to have more than 4 drives unless your backups are instantly up to date. You increase your probability of a drive failure with every drive you add, not to mention the extra power requirements and heat generation.

Also, while 1+0 will pretty much always beat a cheap RAID 5, an Areca with 256MB onboard cache and dedicated processor is going to be hard to beat with some cheapo 1+0 solution. And with that card running RAID 6, your reliability is much higher, plus you have the option of a hot spare.

Cheap <--> Reliable <--> Fast

Pickt two.

[jeff_rys]

allow me to jump in here. My Poweredge 2600 is loaded with 6 drives. First i used Raid5, i switched to Raid10, BUT no real gain in speed here.

Afterall even the PERC4 works sequential.

But, i managed to get 2 drives killed. As you know if you have 6 drives you can allow yourself to loose 3 if not in the same Raid1.

I ordered 5 drives in Germany, because i needed 18 gigs and did not want to buy 36 gigs, loosing 18 gigs in the Raid10.

Only one of the 5 second hand drives works. Guess what 30 minutes after installing that one good drive the one above the "new" installed failed. I almost got a heart attack.

That was it for me. I have 2 old Quantums 10 k's (the six where 15K's) and installed those in order to get my RAID10 back in shape.

Although those old Quantum's are only 10K's the Raid is restored.

So i would say: go for the RAID10, but only for protection, not speed.

I will never, ever go to RAID5 again in my server environment.

The only problem that can occur for anyone.....you loose half of your gig's and Scsi, unfortunately are not for size like Ide drives, ATA, SATA, whatever.

Jeff

[stone cold steve austin]

RAID 10 is always faster than Raid 5

SCSA

[RyanH]

RAID 10 is faster than RAID 5 especially in writes. In reads, it might not be a whole lot faster. You'll really notice the difference if you're performing writes that are greater than the cache on the controller.

[Atamido]

RAID 0+1 is faster than anything else, but it's level of reliablity tanks when the number of drives increase compared to RAID 6.

Some calculations about reliability are availabile here. (There was a recent study about this that I can't seem to track down.)

If you don't need super high speed writes, then go RAID 6. If you need fairly high speed writes, get a RAID 6 card with a decent cache. If speed is your primary concern, you aren't using more than 4 drives, and your backups are always current, go RAID 0+1.

[jeff_rys]

in my opinion Raid 01 is not the same as Raid10. Correct me if wrong.

Anyway, my Raid 10 is not NOTICABLE faster then my previous Raid5.

6 15k's Ultra320 and a PerC4 card.
When you put in the disk(s) that come with the PE2600 (you know with explanations, setups....it is clearly said "read/writes" happen sequentially, so do not think that the (in my case) 3 drives in the Raid0 get attacked all at the same time, they get there actions one by one. So?

I am not so in the tests giving you wonderful figures. It is the daily use i am interested in. So again, others may experience this differently, but, i am only using Raid10 for protection.

Jeff