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Server 2008 / RAID configuration advice
Looking for good advice on partitioning and reasons behind any suggestions please.
Installing MS Server Standard 2008 R2 64 bit OS on a new Dell PE R720 server. It currently has (7) 1TB drives, none configured on a PERC H710 RAID controller. The device primarily will be a file server and host to Backup Exec and a media library.
The thought is RAID 1 for the OS on a 40GB or 60GB partition first, and division of the remainder potentially twice for Program Files and an additional partition for data easily excluded from backups; i.e. copies of CD or other data easily replaced. 1GB drives are larger than needed but having been dealt this hand this seems a reasonable way to go.
The remaining (5) drives would be used in a RAID 5 array. If the controller supports it (anyone verify?), the idea of 4 drives with one fail-over spare is appealing. I anticipate single partition use for this array though I've noted recommendations to split as well.
Best practices? Thoughts please?
Installing MS Server Standard 2008 R2 64 bit OS on a new Dell PE R720 server. It currently has (7) 1TB drives, none configured on a PERC H710 RAID controller. The device primarily will be a file server and host to Backup Exec and a media library.
The thought is RAID 1 for the OS on a 40GB or 60GB partition first, and division of the remainder potentially twice for Program Files and an additional partition for data easily excluded from backups; i.e. copies of CD or other data easily replaced. 1GB drives are larger than needed but having been dealt this hand this seems a reasonable way to go.
The remaining (5) drives would be used in a RAID 5 array. If the controller supports it (anyone verify?), the idea of 4 drives with one fail-over spare is appealing. I anticipate single partition use for this array though I've noted recommendations to split as well.
Best practices? Thoughts please?
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setasoujiro
However I don't see the benefit of partitioning the OS drive for the program files etc..
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ASKER
Thanks for the feedback, it appears I'm on target, but I remain unclear on OS partition size.
In the past I've seen Program Files located on a separate drive - perhaps this was due to the OS being stuck for example on a too small 12GB partition.
I've seen it commented that the OS partition should be smaller, obviously less than the entire available 1 TB drives provide. 100GB was suggested, and Program Files can remain on C:\, so there is no need for a separate swap file location either? I'm okay with this, just looking for any good reason I would need to do otherwise. I'll split (or not) the remaining ~900GB as I please then.
In the past I've seen Program Files located on a separate drive - perhaps this was due to the OS being stuck for example on a too small 12GB partition.
I've seen it commented that the OS partition should be smaller, obviously less than the entire available 1 TB drives provide. 100GB was suggested, and Program Files can remain on C:\, so there is no need for a separate swap file location either? I'm okay with this, just looking for any good reason I would need to do otherwise. I'll split (or not) the remaining ~900GB as I please then.
ASKER
dlethe:
Just saw your comment regarding RAID6. In planning this I see that I may have less free space available than desirable.
Is the following a correct assessment?
RAID 5, 4 1TB drives, 1 hot spare = 3TB total
RAID 6, 4 1TB drives, 1 hot spare = 2TB total
RAID 6, 5 1TB drives, 0 hot spare = 2.5TB total
Considering that the 7th drive would otherwise be configured as a global hot spare, using all 5 drives in an active RAID6 array would not make this available to the OS RAID 1 array in the event of drive failure, correct?
This plot thickens...
Just saw your comment regarding RAID6. In planning this I see that I may have less free space available than desirable.
Is the following a correct assessment?
RAID 5, 4 1TB drives, 1 hot spare = 3TB total
RAID 6, 4 1TB drives, 1 hot spare = 2TB total
RAID 6, 5 1TB drives, 0 hot spare = 2.5TB total
Considering that the 7th drive would otherwise be configured as a global hot spare, using all 5 drives in an active RAID6 array would not make this available to the OS RAID 1 array in the event of drive failure, correct?
This plot thickens...
RAID 6, 5 1TB drives, 0 hot spare = 2.5TB total
This would be 3TB total. Two-disks' worth of storage is used for parity in RAID 6 (4-disk = 2xGB, 6-disk = 4xGB, etc.). RAID 6 is practically using a hot-spare that does not have to wait for a disk to fail to protect the RAID - it is actively participating and protecting the array at all times.
This would be 3TB total. Two-disks' worth of storage is used for parity in RAID 6 (4-disk = 2xGB, 6-disk = 4xGB, etc.). RAID 6 is practically using a hot-spare that does not have to wait for a disk to fail to protect the RAID - it is actively participating and protecting the array at all times.
ASKER
Thank you, I see the error in my math.
"it is actively participating and protecting the array at all times" is of benefit for sure, but the downside is that it becomes unavailable as a RAID 1 hot spare drive. Hmmm...
"it is actively participating and protecting the array at all times" is of benefit for sure, but the downside is that it becomes unavailable as a RAID 1 hot spare drive. Hmmm...
True.
There is no free lunch, obviously. What is more important, to save a few dollars on disk; or to not risk partial data loss in event of a single drive failure; or to not risk 100% data loss if a drive fails during a rebuild.
If the data worth more than a few hundred dollars, then you know what the correct answer is going to be.
If the data worth more than a few hundred dollars, then you know what the correct answer is going to be.
ASKER
Thanks to all. To be fair I split points evenly, each of you offered timely and relevant guidance.
I won't concern myself with special OS related partitions but will allow ample drive space.
I'm on the fence at the moment regarding achieving the capacity needed and ultimate reliability of a RAID 6 configuration but at the expense of not having a hot swap drive available for the OS RAID 1 array. Yes, data integrity is certainly critical, but since I'll maintain daily differential and complete weekly backups I may just swing with RAID 5 leaving a universal hot swap drive available to either array.
I won't concern myself with special OS related partitions but will allow ample drive space.
I'm on the fence at the moment regarding achieving the capacity needed and ultimate reliability of a RAID 6 configuration but at the expense of not having a hot swap drive available for the OS RAID 1 array. Yes, data integrity is certainly critical, but since I'll maintain daily differential and complete weekly backups I may just swing with RAID 5 leaving a universal hot swap drive available to either array.