2011-07-19 04:07 AM
We are have recently upgraded our FAS6070 to Data OnTap 8.0.2 - we now need to update it to a more optimal configuration.
The FAS6070 currently has 524 x 500GB disks.
4 disks will be used for aggr0 leaving 520 disks.
We are looking at 2 options for RAID Group Sizing - 16 or 19 disk RAID Groups
With 16 disk RAID groups we would get:
2 aggregates each consisting of 256 disks (16 RG) giving approx usable aggr size of 154TB (77TB in each aggregate)
Leaving 8 disks spare
With 19 disk RAID groups we would get:
2 aggregates 1 with 247 disks (13 RG) and the other with 266 disks (14 RG) giving approx usable aggr size of 161TB (83TB in 1 aggregate, 77TB in the other aggregate)
Leaving 7 disks spare
Are there any performance disadvantages to using 19 disk RAID groups, as compared to using 16 disk RAID groups?
We obviously want to get the maximum storage capacity possible but also want to avoid unecessary risk or performance degradation.
Any advice would be helpful.
2011-07-19 04:45 AM
First of all, with FAS6070 you have a 100TB limit for a 64-bit aggregate (unless something has changed between 8.0.1 & 8.0.2).
RAID group size mainly impacts a rebuild time, should any drive fail in that group - the bigger the group is, the longer it takes.