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I have had some problems using hardware-RAID on a server. Now I'm planning to use the Windows Server built-in software-RAID-1 instead. The server will only be used for Business Administrations, so I don't need high performance. The operating system is Small Business Server 2008 and the server is HP ProLiant DL320 G6.

Are there any disadvantages by using the Windows Server 2008 built-in software-RAID for mirroring?

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up vote 4 down vote accepted

There's a few disadvantages. Not many. Probably not enough to outweigh the advantages of having a software RAID.

  • Everyday performance is going to suffer...minimally...probably not noticeably at all
  • Rebuilding the RAID is going to kill performance...probably a lot
  • Software RAIDs typically don't give you hot swap ability, meaning a failed drive requires downtime
  • The RAID is OS dependent...not a big deal for most, but some people need to dual boot.
  • Dynamic disks don't work that well with recovery tools

All that said, you have the advantages of hardware portability, not having a RAID card as a point of failure, and much better pricing. I'm really a fan of software RAID 1 (as long as I don't need hotswapping)...not so much a fan of software RAID 5, but that wasn't really the question :-)

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+1 - Windows software RAID-1 is cheap insurance and works pretty well. – Evan Anderson Sep 14 '10 at 1:53
+1 Great answer. Thanks. – Jonas Sep 14 '10 at 9:25
When I used hardware-RAID, rebuilding the RAID also killed the performance a lot. – Jonas Sep 14 '10 at 9:27
why are you not a fan of Software Raid5?? because of the missing hotswap function? – wurlog Nov 17 '10 at 17:51
Not a fan of software RAID5 mostly because of the NOTICEABLE performance hit. With RAID 5/6, parities should be calculated on hardware. Lack of hotswap is also a consideration. A degraded RAID 5 is much more vulnerable than a degraded RAID 1 (more drives that can fail and lose everything). I'd rather not put the "healthy" drives through the unneeded stress of a power cycle. – Jason Berg Nov 18 '10 at 23:26

In order to use Windows software RAID you need to run "dynamic" disks. That in itself can be a real problem when things go wrong, because most recovery tools won't work well, if at all, with dynamic disks.

If you are having problems with hardware RAID you need to discuss it with the manufacturer and vendor. Good quality hardware RAID (servers should never run low quality hardware) has a long proven history of reliability and disaster recovery is more reliable.

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Aren't low-level recovery tools only for people who don't have a backup/DR strategy in place prior to a failure? – Skyhawk Sep 13 '10 at 23:45
@Miles - Since when is RAID 1 considered a backup? You can still screw up filesystems and partition tables on a RAID1 – Jason Berg Sep 13 '10 at 23:52
@Miles, most backup strategies don't involve taking backups during the day; and sometimes recovery can take longer than a simple low level fix. More options are always better. – Chris S Sep 13 '10 at 23:57
@Miles, as Chris indicates, a full recovery isn't always the best strategy. I personally like to leave as many DR options open as I reasonably can. – John Gardeniers Sep 14 '10 at 0:52
@Jason: That was my point. @Chris/John: Makes sense. I've never been party to a simple low-level fix, but that certainly doesn't mean they don't exist. – Skyhawk Sep 14 '10 at 15:17

Since you're not concerned about disk performance, the biggest thing to note - It will convert your disks from "basic disks" to "dynamic disks". this means a lot of utility/partition programs will have problems with it in the future. IE. problems resizing partitions, if you need to do data recovery can be more tricky.

You probably (hopefully) will never need to fight with lowlevel disk utilities but that is the biggest disadvantage i've personally had.

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Good point about the resizing point. RAID-1 volumes on Windows can't be increased in size. If you're on stand alone media already this may not be a problem, but if you're in a SAN or VM environment it can be killer. – sysadmin1138 Sep 13 '10 at 23:44
You don't need to use third-party partitioning programs to resize volumes on Windows 2008. For instance to migrate from a small disk to a RAID array I simply added a mirror, then when the disks had synchronised I removed the original partition and expanded the volume. – Neil Oct 7 '10 at 15:26

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