A change to sub-blocks on VMFS-6

Something that I only just recently noticed is that we have made a change to the sub-blocks structure on VMFS-6, compared to VMFS-5. Sub-blocks are small allocations on a VMFS volume, and they are used to back small files. They were introduced as a space-saving measure to prevent using a full file block to back a very small file. To put this simply, when a [...]

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Heads Up! VOMA – ERROR: Trying to do IO beyond device Size

This is a short note on trying to use VOMA, the vSphere On-disk Metadata Analyzer, on a dump taken from a VMFS-5 volume which was upgraded from VMFS-3. This is not an issue if [...]

Condusiv V-locity 4 – New caching feature

I recently got hold of a copy of the new V-locity 4 product from Condusiv which was released last month. Condusiv is the new name for Diskeeper, whom you may have heard of [...]

Heads Up! Storage DRS scheduler removes rules

One of my friends over in VMware support just gave me a heads-up on this issue. It affects virtual machines with anti-affinity VMDK rules defined (for keeping virtual machine [...]

Auto LUN Discovery on ESXi hosts

Did you know that any newly presented LUNs/paths added to an already discovered target will automatically be discovered by your ESXi host without a rescan of the SAN? In this [...]

VOMA – Found X actively heartbeating hosts on device

One of the long-awaited features introduced with vSphere 5.1 was VOMA (vSphere On-disk Metadata Analyzer). This is essentially a filesystem checker for both the VMFS metadata [...]

Error while adding NFS mount: NFS connection limit reached!

The advanced setting SunRPC.MaxConnPerIP defines the maximum number of unique TCP connections that can be opened for a given IP address. This is of particular interest to [...]

vCenter Server 5.1.0b Released

This is a follow-up to my previous post on the 5.0U2. At the same time, VMware also released vCenter 5.1.0b. This post will look at the storage items which were addressed in [...]