Question
· Jul 30

disk provisioning in a SSD environment

Hi we are migrating to Linux from OpenVMS. which includes a new server and SAN. after reading a prior post about the differences with ESX and a VSAN I would think that the a SAN with Virtual disks all SSD type would be similar. which after reading it makes me think that using thick provisioning is the way to go. the 3rd party vendor is arguing this point with me.  is it the same premise?  is non-dedupe the way to go with thick provisioning.  we are currently on 2015.2 of Cache with the plans to go to 2018 until the app vendor is able to certify their product on the latest versin.

thanks

Paul

 

VMware vStorage APIs for Array Integration (VAAI)

For the best storage performance, customers should consider using VAAI-capable storage hardware. VAAI can improve the performance in several areas including virtual machine provisioning and of thin-provisioned virtual disks. VAAI may be available as a firmware update from the array vendor for older arrays.

Virtual Disk Types

ESXi supports multiple virtual disk types:

Thick Provisioned – where space is allocated at creation. There are further types:

  • Eager Zeroed – writes 0’s to the entire drive. This increases the time it takes to create the disk, but results in the best performance, even on the first write to each block.
  • Lazy Zeroed – writes 0’s as each block is first written to. Lazy zero results in a shorter creation time, but reduced performance the first time a block is written to. Subsequent writes, however, have the same performance as on eager-zeroed thick disks.

Thin Provisioned – where space is allocated and zeroed upon write. There is a higher I/O cost (similar to that of lazy-zeroed thick disks) during the first write to an unwritten file block, but on subsequent writes thin-provisioned disks have the same performance as eager-zeroed thick disks

In all disk types VAAI can improve performance by offloading operations to the storage array. Some arrays also support thin provisioning at the array level, do not thin provision ESXi disks on thin provisioned array storage as there can be conflicts in provisioning and management.

Product version: Caché 2015.1
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