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Category: Storage

General vSAN Error

General vSAN Error

vSAN is a wonderful shared storage option in a vSphere cluster, but it requires an administrator with deep product knowledge and overall awareness to be able to manage it with an understanding of its quirks and gotchas. I’ve worked with several vSAN clusters composed of many nodes for a few years now but sometimes it still surprises me. I’ve recently spent a couple of hours troubleshooting a “General vSAN Error” to figure out why I couldn’t put a host in…

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VSAN real capacity utilization

VSAN real capacity utilization

There are a few caveats that make the calculation and planning of VSAN capacity tough and gets even harder when you try to map it with real consumption on the VSAN datastore level. VSAN disks objects are thin provisioned by default. Configuring full reservation of storage space through Object Space Reservation rule in Storage Policy, does not mean disk object block will be inflated on a datastore. This only means the space will be reserved and showed as used in VSAN Datastore…

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Perennially reservations weird behaviour whilst not configured correctly

Perennially reservations weird behaviour whilst not configured correctly

Whilst using RDM disks in your environment you might notice long (even extremely long) boot time of your ESXi hosts. That’s because ESXi host uses a different technique to determine if Raw Device Mapped (RDM) LUNs are used for MSCS cluster devices, by introducing a configuration flag to mark each device as perennially reserved that is participating in an MSCS cluster. During the start of an ESXi host, the storage mid-layer attempts to discover all devices presented to an ESXi host…

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vSphere 6.5 – Stronger security with NFS 4.1

vSphere 6.5 – Stronger security with NFS 4.1

NFS 4.1 is been supported since vSphere 6.0 and  but now we are looking into providing stronger security. In vSphere 6.5 we have better security  by providing strong cryptographic algorithms with Kerberos (AES). Also, IPV6 is supported but not with Kerberos and that is another area we are looking into along with supporting integrity checks. Aa we know vSphere 6 NFS client also does not support the more advanced encryption type know is AES. So lets take a look at…

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vSphere 6.5 – New scale limits for paths & LUNs

vSphere 6.5 – New scale limits for paths & LUNs

In vSphere 6.5 VMware  doubled  the  current limits and continuously work on reaching new scale around this . Current limits (before 6.5) pose challenge as for example in some cases our customers have 8 paths to a LUN, in this configuration one can have max of 128 LUNs in a cluster. Also, many of the customers tend to have smaller size LUNs to segregate important data for easy backup and restore. This approach can also exhaust current LUN and Path…

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vSphere 6.5 – Automatic UNMAP

vSphere 6.5 – Automatic UNMAP

In vSphere 6.5 VMware are looking into automating the UNMAP process, where VMFS  would track the deleted blocks and will be able to reclaim deleted space from the backend array in back ground. This background operation should make sure that there is a minimal storage I/O impact due to UNMAP operations. Just to remaind – UNMAP is a VAAI primitive using which we can reclaim dead or stranded space on thinly provisioned VMFS volume. Currently this can be initiated by…

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vSphere 6.5 – VMFS6 & 512e HDD support

vSphere 6.5 – VMFS6 & 512e HDD support

vSphere 6.5 introduces a new VMFS 6 – but why we need new version You ask? –answer: to support new hdd type, and this  point  us to current storage market situation . Well because with  512bytes sector size HDD’s  vendors are hitting drive capacity limits. They can not go beyond a certain size without compromising the resilience and reliability (not the best option in case of our data).             To provide large capacity drives, Storage Industry is moving forward to Advance…

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Increase VMware ESXi iSCSI storage performance ? – lets demistyfy all tips and tricks

Increase VMware ESXi iSCSI storage performance ? – lets demistyfy all tips and tricks

  Before we start I would like to describe main motivation to write this article which is quite simple – to gather in one place all basic theoretical background about iscsi protocol and best practices at its implementation on vSphere platform with special consideration about potential performance tuning tips & tricks . This is first part of the series where We (I’m counting on readers participation) try to gather and verify all this “magical” parameters often treated as myths by…

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