VMware Communities: Open unofficial storage performance thread

EMC Symmetrix: Calculations for Heads, Tracks, Cylinders, GB

New World Record: 1,000,000 IOps from vSphere 5

Dynamic Disks with Windows Server Failover Clustering

This article provides a very good overview of the issues involved in the use of dynamic disks with Windows Server Clustering.

What is NetApp's Flash Cache?

Veritas Storage Foundation and NTFS File Cluster Sizing

I ran a few tests recently to figure out if I/Os might be crossing cache boundaries when the NTFS file cluster size is increased beyond 32Kb. Veritas Storage Foundation VEA default Track Alignment offset for EMC Symmetrix arrays (we use VMAX) is 64 sectors (32 Kbytes). In theory, using a 64Kb NTFS file cluster size may push I/Os across storage cache boundaries and reduce throughput. For more information on the effects of incorrect Track Alignment see here.

This seems to be the case based on the throughput improvements seen below with 64k cluster sizing and 2048 sector offset, see below. Increasing the Track Offset to 2048 sectors increases throughput substantially.

If we start using >32Kb NTFS cluster sizes on any of our Veritas equipped Wintel fleet we'll need to alter the default Track Alignment settings in VEA from 64 to 2048 sectors.

New white paper providing guidance for sizing NTFS volumes