RAID 5 or RAID 10 - Which is the best?
Posted by wolfdog, 04-19-2009, 08:48 AM Hi, The answer to my previous seems to HARDWARE RAID because of the ability of the server to still function during a rebuild. The hardware is 4 X 1TB Western Digital RE3 Drives However which configuration would you suggest, RAID 5 or RAID 10? Thank You Wolfdog
Posted by Robert vd Boorn, 04-19-2009, 08:50 AM http://weblogs.sqlteam.com/billg/arc...rformance.aspx A very long arcticle from microsoft: http://technet.microsoft.com/nl-nl/l...14(en-us).aspx RAID 10.
Posted by linktome, 04-19-2009, 08:55 AM Raid 10 hand down
Posted by eth00, 04-19-2009, 09:00 AM Generally for most situations RAID10 over 5 hands down.
Posted by gavint, 04-19-2009, 09:10 AM It depends on your requirements - for anything with a heavy write load then RAID 10 will be the best choice, if you can afford to lose 50% of the space. For reads you may find RAID 5 is better. Gavin
Posted by FHDave, 04-19-2009, 09:11 AM well, depends ... Not sure why some are quick to give their answers without knowing the intended use. For web server, RAID10 does not give much advantage. Web server has very low write I/O and RAID5, that has high penalty for write operation (due to parity calculation), works just fine in this environment. And depending on the number of spindles you have, RAID5 can give you quite a high read I/O. For database/email server (or any server with high I/O), you do not want to use RAID5 due to its parity penalty. RAID10 would be beneficial here due to its high write I/O. Note, however, the 50% penalty you would pay for space efficiency. For backup server, RAID5 may work just fine. Though it's slow for write, backup server is not as important as other, so the slow write may be acceptable. Besides, you do not want to pay 50% penalty on your storage size. Have you considered RAID50?
Posted by Syslint, 04-19-2009, 09:20 AM Raid 10 I prefer
Posted by JFSG, 04-19-2009, 09:30 AM I would want to know what are you going to use the server for? Different RAID configurations may suit different needs.
Posted by wolfdog, 04-19-2009, 10:25 AM Hi Thank You for your help This server will host Wordpress Blogs and Joomla sites. I assume lots of reads, periodic writes Wolfdog
Posted by JFSG, 04-19-2009, 10:27 AM RAID 10 should be the way to go then. If not, RAID 1 will just do fine too.
Posted by serveradmin4u, 04-19-2009, 10:31 AM Raid 10 because it has data redundancy and performance Serveradmin4u
Posted by Collabora, 04-19-2009, 12:07 PM For your use you will not notice the write-performance gains from RAID 10 RAID 5 will be less expensive to set up but a little more expensive for recovery (especially considering performance degradation during failure) Its your call! Always use hardware raid - not just for the rebuild factors, but during normal operations all parity calculations, drive instructions, etc are off-loaded to the controller card instead of run on the server cpu and os.
Posted by FHDave, 04-19-2009, 05:04 PM Where is the database located? If this only serves as web server, then go with RAID5. I think those suggesting RAID10 so quickly may not have experience with different RAID (but RAID10, understandable since they keep forcing using RAID10 for all needs) or understand different kind of RAID setups. How many drives do you have? If you have at least 6 drives and you don't want to have RAID5, then consider RAID50. Total capacity on RAID50 is still bigger than RAID10, it offers faster write speed than RAID5 (which may matter to you if you host the database on the same server), and it offers better redundacy, better than RAID5. Last edited by FHDave; 04-19-2009 at 05:09 PM.
Posted by Maars, 04-22-2009, 03:59 AM If data reliability is the prime concern then maybe RAID6
Posted by linuxfan, 04-22-2009, 08:54 AM I would go with raid 10
Posted by KoiKoo, 04-22-2009, 09:03 AM RAID 10 all the way.
Posted by rankris, 04-22-2009, 09:23 AM raid 10 without any doubt
Posted by Arun - HostLevel3, 04-22-2009, 09:39 AM Everyone singing RAID10, but if data reliability is the main concern, even then do you recommend RAID10? Remember in RAID10 if 2 disks of the same pair fail, then data is lost !!! For such case RAID6 is better.
Posted by fwaggle, 04-22-2009, 02:09 PM IMHO, most people "recommend RAID10" because if you have four+ disks it's never really a "wrong" answer. There's a few situations where another answer is more "right", but no one ever got fired for setting up RAID10 - which is why you end up with people recommending it without knowing the intended use of the array.
Posted by skypn, 04-22-2009, 02:15 PM Now this is Very Educating, thank you Arun
Posted by SenseiSteve, 04-22-2009, 02:17 PM I don't think there's a hard fast answer here. RAID10 is a suitalbe solution, whereas others have noted other arrays may be a better match for the intended use.
Posted by biggies, 04-22-2009, 04:09 PM Raid 10 is the best. They also call it Raid ADG.
Posted by quad3datwork, 04-22-2009, 04:49 PM RAID10 If you don't mind losing more space.
Posted by Arun - HostLevel3, 04-22-2009, 05:11 PM Wow with that dance, i too go with RAID10 then
Posted by FHDave, 04-22-2009, 05:12 PM I doubt most of those recommending RAID10 here have no experience with RAID5 (with 6 drives or more), RAID50, RAID6, etc.
Posted by quad3datwork, 04-22-2009, 06:07 PM OP gave the specs. Do you mind sharing what you have in mind? For larger setups, I do prefer RAID5 with at least 2 spares or RAID6 with spares. Better yet, >ZFS<. 30+ spindles on ZFS screams!
Posted by AstroNyu, 04-22-2009, 06:21 PM With raid 50, will most raid controller support it? Which is better, 8x500GB in raid 10 or raid 50?
Posted by hittjw, 04-22-2009, 09:59 PM You want to consider what kind of controller you are using and what kind of RAID it supports. You also need to look at what kind of recovery is necessary. Another consideration is if you can hot-spare drives. If you can't swap the disks you'll still have downtime on a failure, so why not use as much space available. Best, Justin
Posted by mugo, 04-23-2009, 02:50 AM With your 4 X 1TB - Raid 10, = 2TB raw usable space, if you loose match sets, you'll loose data. Small chance, less mathematical chance as raid 5 w/ no HS, because you only have 50% chance of loosing 2 of the wrong drives. with 4 drives / Raid 5, losing 2 will result in data loss, array failure regardless of which drives they are. Raid 6 (3 Strp + 1 HS), 2TB raw usable space (across 3 drives), 1 Hot spare waiting for array member to fail. Can loose 2 drives, loosing 3 results in data loss, array failure. Raid 5 (4 Strp , no HS), 3TB raw space, can loose 1 drive, loosing 2 results in data loss, array failure. Of course, Raid should be only considered for continuity during HD failure, not a backup technique. The probability that you will loose 2 drives before replacing a bad one is very slim, independent scheduled backup should assure no data loss. Personally, the choice for your app would be either Raid 10 or 5. With 5, you get an extra TB of space to play with. In 15 years of Raid management, I have had ONE server kill two drives at once, and that was due to an electrical grounding issue (idiot wiring backplane). I'm referring to well over 500 Raid configured servers. If you'll never, ever use 2TB, go with R10. If you salivate over 3TB, make it a R5. I seriously doubt you'll ever notice any I/O difference unless you end up loading MSSQL with lots of data one day. Hope that helps. Last edited by mugo; 04-23-2009 at 02:54 AM.
Posted by ewindisch, 04-23-2009, 03:59 AM It depends on what the workload is. I'm doing heavy virtualization workloads and have settled on RAID-10 purely for the performance aspect. Even serving a budget market, I decided that the additional cost of building out a high performane solution was worth it to prevent complaints and involve less SA time. Be mindful that your caching strategy is also vital. Personally, I'm running 10 x 1TB disks in RAID-10 with an on-controller cache, using software mirroring and striping via ZFS, benefiting from OpenSolaris' ARC cache, and I yet have the options of adding a SSD cache for "hybrid storage" and increasing my RAM-based caches. You won't see nearly the same performance if you just throw 10 disks into an old Linux box, run mdadm, and walk away.
Posted by mugo, 04-23-2009, 04:04 AM He stated his workload. Based my answer on that.