What RAID level is Right for U?
Posted in Storage Interconnects & RAID, Advisor - Steve Rogers by Steve RogersWe should all know that adding RAID to your storage configurations is one of the most cost-effective ways to maintain both data protection and data availability; but what RAID level is most appropriate?
To choose the RAID level that’s right for you, begin by considering these five factors:
• The number of Host-side and Array-side RAID controllers in the storage configuration.
• The amount of cache in the storage array(s)
• The disk capacity addressable in each storage array
• The storage performance requirements of the application – workload - random (IOPS) and sequential (MB/sec)
• The rotational speed or rpm and access times of each disk in the storage array. The disk manufacturer usually provides these.
At the link below you’ll a quick comparison chart that should help you pick the most appropriate RAID type for your needs.
http://graphics.adaptec.com/pdfs/RAID_level_compar_chart-revised.pdf
SR
October 19th, 2006 at 4:59 am
I’m torn between RAID 5 and 10. I want a killer workstation, money is not the deciding factor. I have 4 10,000 rpm Raptor drives, and will use a controller card (not the onboard controller on the MB). I want speed and fault tolerance.
October 23rd, 2006 at 5:31 am
Anyone out there. What’s the purpose of this blog if nobody responds.
October 24th, 2006 at 6:08 am
I’ll ping Steve. He may not have saw your comment.
But I can help answer your question.
First, how often do you do short random writes? RAID-5 could be 2-4X slower than RAID-10. On long random writes, RAID-5 will only be slightly slower than RAID-10. On reads, both RAID levels will have very similar performance.
Second, you said money is not a factor. But is drive count a factor? Or put another way, is capacity a factor? If neither are a factor, go with RAID-10. It’s always faster than RAID-5.
But if you just can’t get to the capacity point you want with RAID-10 given a limited number of drive bays, then you’re going to decide which bothers you more - the drop in performance with RAID-5 or the drop in capacity with RAID-10.
TT
October 24th, 2006 at 12:57 pm
To add what Tom has covered in two areas:
Capacity - Depending on your capacity needs - both current and future -you may find yourself limited because of the drive count and limits of your chassis or storage adaptor should you choose RAID 10. Here, you can go to an expansion array to give you the drive count you need.
RAID 10 - if you also are extremely paranoid about your data I would choose RAID 10. It is used by some of the most discreminate of applications and markets. For instance, Drug companies like RAID 10 because tat cannot lose data. With RAID 10 you can lose a drive from each RAID 1 mirror and still maintain data availability. RAID 10 is much more failure resilent than RAID 5.
lastly, should you choose a RAID 5 configuration, I can’t stress this enough - put your system on a UPS!!!
SR
October 26th, 2006 at 12:19 pm
That settles it, I’m going RAID-10 this time. Thanks guys
November 15th, 2006 at 3:58 pm
Here’s a followup question about RAID 10. Since there isn’t as much computations going on with RAID 10 as compared to RAID 5, would there be much of a performance difference between an onboard RAID controller vs a third-party controller card?
January 5th, 2007 at 6:12 am
Hi,. im having some trouble fully understanding which RAID set is best for me. Im setting up a home recording studio and my aim is to have, to begin with, 4 500gb sata drives. I want 2 sets of striped sets (2 1tb disks) but i also want them to mirror each other. Speed isnt a factor, i dont care how long this takes to access etc. The inclusive factors are capacity and reliability. Ive been looking at an Adaptec 2610SA with 6 ports as this gives the the option to expand as well.
Please could you enlighten me as to which RAID set and adapter to go for.
Thanks for all your time
Greg
February 25th, 2007 at 10:03 pm
that’s raid 10
March 16th, 2007 at 3:54 am
Please make it simple… is the only reason one would not use 10 (0+1) over 5 the cost of the second drive?
Or is the trade off the cost of the second drive, the chassis to hold it, and that you can only use the space of one physical drive?
1. Money not an object!
2. Chassis not an object!
3. Security and speed is the object!
Thanks, God bless and great day,
Gary Matthews
March 16th, 2007 at 5:11 am
Gary, if you have enough chassis space and enough money, then you should always pick RAID-10 over RAID-5. Performance will be better and rebuilds will be better. But I don’t know what you mean by security. Do you mean reliability? If so, they both tolerate a single drive failure. However RAID-10 can tolerate more than one drive failure if each failure is in a different RAID-1 pair. And RAID-10 is more tolerant to bit errors during rebuild because there is less capacity involved in each rebuild. So with that definition, RAID-10 is more reliable than RAID-5.
BTW, the only time you would choose to NOT use RAID-10 is if you wanted to tolerate two drive failures or errors during a rebuild. In that case you’re only choice is RAID-6.
TT
September 10th, 2007 at 6:12 am
Hi, i actually have the Adaptec 2610SA in an HP storage server with 6 250 gb disks attached, works fine.
What i want to know is, how much disk capacity does the Adaptec 2610SA support ? Can I exchange the 250 gb disks for 500 or even 750 gb ones ? Is there an issue with the adapter bios ?