emc 181gb drives

[Rpger Tavener]

Has anyone had any issues with EMC Symmetrix using the 181GB drives? They seem much slower than the 72 GB that we previously used. Also, I understand that the 181GB drives may no longer be available??

Thanks

[Peter Mattei]

Well, I do not have hands on experience with Symmetrices, but we also sell the 181GB drives for our older XP models, the XP48 and the XP512. (Beside 36, 47, 72 and soon 146GB 10krmp drives)
You are right; they are slow and only spin at 7200rpm, so average latency is around 8ms compared to 6ms on a 10krpm drive or 4ms on a 15krpm drive.
Another thing to consider is random performance which directly correlates to spindle count. Rule of thumb is: the more spindles in an array the more performance you can get out of it, if the controller is not the bottleneck!
If you let's say provide 10TB raw capacity, this will be round 55* 181GB disks or 139* 72GB disk or even 278* 36GB disks.
So for sequential IO you are fine, for random workloads I would never use the 181GB 7200rpm drives.
Cheers
Peter