Here are some notes I find useful for anyone wanting to learn more about the latest that HDS has to offer. Please note the date of this post and that something are subject to change.
1.Thin Provisioning > Unmap primitive WILL not be availible until Q1 2012
PER HDS > Reason being is that the UNMAP primitive when issued from VMware ESXi (vSphere 5) causes all the workloads on the Provisioned Storage Pool
to take a performance hit. This is because the UNMAP is issued with a “high priority”.
The KB provides how to disable this feature.. It IS NOT disabled by default. This is a command ran locally on each ESXi 5 host.
2. sVmotions, VMDK deletions on various storage platforms with ANY thin provisioned Arrays will always be showns as space allocated. (The space is never reclaimed) To counter this negative effect UNMAP was introduced however is not production ready and causes problems.
3. Round – Robin PSP – is the HDS best practice for multi-pathing. HOWEVER we cannot do any clustering (MSCS or Oracle RAC) with this plug-in or AKA – Physical Compatible Raw Device Mappings. (VMs accessing physical SAN LUNS vs. VMFS) However HDS has released HDLM which is the HDS branded VMware Multi-Path Plug in and you can do both with this plug-in.
4. Block Size on HDS is 42MB – with vSphere 5 unified block size of 1 MB HDS arrays have to delete more blocks due to the unified block sizing. Stated that proper alignment is important between SAN, VMFS, and VMs.
5. Tier 1 Applications need special consideration depending on the use case – we may need to look at dedicating a particular level of Guaranteed I/O or creating seperate Dynamic Storage pools to meet the workloads. There is HDS documentation for using VSP with vCloud Director however it doesn’t cover application workloads > waiting for these from HDS as we virtualize MANY different workloads in our cloud and it needs to scale easily on demand.
7. vCenter plug in – more to come..
8. I/O and measurements for performance on the SAN side is done through Performance Tuner from HDS. More to come.
9. No firmware update should be needed on the HDS side for VSP array to utilize the two new vSphere 5 VAAI primitives. Not sure about AMS…
10. VASA is coming quickly and this will give customers the visibility and deeper reporting for other things especially for VMware environments using HDS storage.
11. HDS recommend doing VMware Guest OS’es as Thick and doing San array thin. However there is not a huge gain in performance between the two. Our direction is to use Thin on Thin provisioning for reporting purposes, and etc..
For more HDS white papers and such you get to those here under a resources tab:
Hitchi Data Systems VMware resources
***Disclaimer: The thoughts and views expressed on VirtualNoob.wordpress.com and Chad King in no way reflect the views or thoughts of his employer or any other views of a company. These are his personal opinions which are formed on his own. Also, products improve over time and some things maybe out of date. Please feel free to contact us and request an update and we will be happy to assist. Thanks!~