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deduplication Flash NFS Snapshots Storage VMware VMworld vSphere

A closer look at Datrium

Datrium are a new storage company who only recently came out of stealth. They are one of the companies that I really wanted to catch up with at VMworld 2015. They have a lot of well-respected individuals on their team, including Boris Weissman, who was a principal engineer at VMware and Brian Biles of Data […]

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Storage VMware VSAN vSphere

SAS Expander support on Virtual SAN

This question has come up on a number of occasions in the past. It usually comes up when there is a question about scalability and the number of disk drives that can be supported on a single host that is participating in Virtual SAN. The configurations maximums for a Virtual SAN node is 5 disk […]

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Snapshots Storage VASA VMware vSphere VVols

The value of Virtual Volumes (VVols)

Regular readers will know that I normally blog about the technical aspects of storage, as opposed to doing opinion pieces. However there have been a number of articles published recently questioning the value of VMware’s Virtual Volumes, commonly referred to as VVols. In general, the pieces I have read ask whether or not VVols (or […]

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Storage VMware VSAN vSphere

VSAN 6.0 Part 9 – Proactive Re-balance

This is another nice new feature of Virtual SAN 6.0. It basically is a directive to VSAN to start re-balancing components belonging to virtual machine objects around all the hosts and all the disks in the cluster. Why might you want to do this? Well, it’s very simple. As VMs are deployed on the VSAN […]

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Storage VMware VSAN vSphere

VSAN 6.0 Part 6 – Maintenance Mode Changes

There is a subtle difference in maintenance mode behaviours between VSAN version 5.5 and VSAN version 6.0. In Virtual SAN version 5.5, when a host is placed into maintenance mode with the “Ensure Accessibility” option, the host is maintenance mode continues to contribute its storage towards the VSAN datastore. In other words, any VMs that […]

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Performance Snapshots Storage VMDK VMware VSAN vSphere

VSAN 6.0 Part 5 – new vsanSparse snapshots

There is a new snapshot format introduced in VSAN 6.0 called vsanSparse. These replace the traditional vmfsSparse format (redo logs). The vmfsSparse format was used when snapshots of VMs were taken in VSAN 5.5, and are also the format used when a snapshot is taken of a VM residing on traditional VMFS and NFS. The […]

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Flash Storage VMware VSAN vSphere

VSAN 6.0 Part 4 – All-Flash VSAN Capacity Tier Considerations

In Virtual SAN version 6.0, VMware introduced support for an all-flash VSAN. In other words, both the caching layer and the capacity layer could be made up of flash-based devices such as SSDs.  However, the mechanism for marking some flash devices as being designated for the capacity layer, while leaving other flash devices as designated […]