I am looking into a configuration on a site where the components of the NBU environment are as follows:
Master Server - W2K8R2, NBU7602
1 x MSDP Media Server - W2K8R2, NBU7602, Server 16 cores, 96GB RAM, Attached disk HP MSA P2000 G3 FC
2 x Media Server - W2K8R2, NBU7602, tape use only
The disk subsystem is dedicated to NBU and attached to the Media server over Fibre Channel. MSA is dual controller - dual port, 24 x 4TB 7.5k rpm SAS disks. Disks are configured into 2 x 12 drive RAID6 sets, one on CTL A and one on CTL B. The site has configured the disk as follows (due to limitations on the MSA presenting LUNs larger than 40TB):
2 x VDISKS - 39.9TB each - chunksize 64KB
The VDISKS are presented to the W2K8R2 server over fibre channel where they have been configured into a single SPANNED dynamic disk of approx 80TB in size.
NBU MSDP pool has been configured with ALL components (database/logs/data) residing on this single volume.
On initial investigations I am seeing performance to local LTO5 tape drives significanlty better than performance of backups to the MSDP pool. I believe the Media Server (16 core, 96GB RAM, 4 x FC interfaces to the storage) is adequate, but when I look at the MSA stats I am seeing CTLA being hammerred and CTLB basically Idle.
I have a couple of concerns here, and am interested in comments relating to any experiences configuring MSDP in a similar environment.
1. Is a single 80TB MSDP pool viable on this configuration ?
2. Best practice states that the database/logs should be seperated fromt the data - i.e. different volume
3. Is it good practice to create a single spanned volume (80TB) in windows of the two VDISKS on the MSA ?
4. Is RAID6 slowing me down here ? Would RAID5 be a preferable option ? (Disks are 4TB 7.5k rpm - slow disk ??)
I am considering re-configuring the MSA to present 2 x 40TB RAID5 volumes, spread accross the controllers, and configuring 2 x MSDP pools to which I would spread the backup load. Whilst we would not benefit from the same Global Dedup I believe this would improve performance.
Any experiences / comments appreciated.
AJ