I just recently received my credentials to VMware’s vCloud Hybrid Services. One of the first things I was interested in testing out was the Disaster Recovery Service, which uses VMware’s vSphere Replication technology to protect VMs in your on-premise DC to vCHS. The following post provides the steps to configure the replication target as your vCHS VDC (virtual data center), and then configuring replication on a VM.
I was involved in some conversations recently on how the VAAI UNMAP command behaved, and what were the characteristics which affected its performance. For those of you who do not know, UNMAP is our mechanism for reclaiming dead or stranded space from thinly provisioned VMFS volumes. Prior to this capability, the ESXi host had no way of informing the storage array that the space that was being previously consumed by a particular VM or file is no longer in use. This meant that the array thought that more space was being consumed than was actually the case. UNMAP, part of…
Although I didn’t attend EMC World this year, there were a lot of interesting announcements. I managed to catch up with Matt Cowger (who sorts of sits between both the EMC & VMware camps) and ran through some of the main highlights from this year’s conference. There has been a lot written about EMC World already (and I mean a lot) so I’m going to try to keep the highlights to a minimum, and provide links to where you can read more.
I had this question recently regarding the best way to format volumes in a Windows 2008 Guest OS, and if there were any considerations with the different formatting types on a volume which resides on a thin provisioned VMDK. Just to be certain that what I was stating was actually true, I set up a small test. Bottom line – use quick format when formatting the volume as a normal format will fill the volume, negating the space-saving associated with thin provisioned volumes.
Many of you will be aware that Storage DRS uses Storage I/O Control (SIOC) for load balancing based on I/O metrics. However a statement in one of our white papers has raised a few questions recently with both our customers and partners. The statement is as follows: “Queue depth throttling is not compatible with Storage DRS”. (pg.34) from http://www.vmware.com/pdf/Perf_Best_Practices_vSphere5.5.pdf. This assertion led many to believe that Storage DRS would not work well with Adaptive Queuing (AQ), another of VMware’s queue depth throttling mechanisms. However internally, many felt that this wasn’t a true statement, but some work was needed to verify…
This is a question that has come up a number of times. Many of you will now be familiar with the VM Storage Policy capability Number Of Failures To Tolerate for VSAN, which defines how many failures can occur in the VSAN cluster and still provide a full copy of the data to allow a virtual machine to remain available. In this short post, I will explain how many physical ESXi hosts you need to accommodate the Number of Failures To Tolerate requirement in the VM Storage Policy.
In this post, we talk about a particular behaviour with using the default (or None) policy with VSAN. I have stated many times in the past that when a VM is deployed on the VSAN datastore, it behaves like it is thinly provisioned unless the capability ‘Object Space Reservation’ (OSR) is specified in the VM Storage Policy. The OSR will pre-allocate space on the VSAN datastore for the virtual machine’s storage objects, and is specified as a percentage of the actual VMDK size. However, there is a slightly different behaviour when the default policy is used. Once again, I was…