VSAN v6 Provision Thick Disk

I always think when creating or migrating VM on a VSAN datastore, its disk should be thin provisioned. However, I discovered some VM disks in our VSAN datastore are “thick” provisioned even all the VM storage policies are set to 0% object space reservation. How is it possible? After some digging, here is what I learn.

Thick Disk Format on VSAN

VSAN defines the disk type (thin or thick) via the Object Space Reservation setting in the VM Storage Policies. By default, this value is 0%, implying the disk is deployed as thin.

If the value is set to 100%, meaning the space for the disk is fully reserved, which can be thought of as full, thick provisioned. This behaves similarly to thick provision lazy zeroed. There is no eager-zeroed thick format on VSAN. (reference: Virtual SAN 6.2 Design and Sizing Guide, page 65)

Benefit to Provision Thick Disk on VSAN

Based on my understanding of VSAN disk IO operating (VSAN mirrors write IOs to all active mirrors, there are acknowledged when they hit the flash buffer!), typically there is no performance difference between thin and lazy zeroed thick provision on VSAN. Remember, there is no eager-zeroed thick format on VSAN (see above). Also see the Yellow-Bricks post. (PS: Duncan’s post may misspeak about VSAN eager zero thick provision.)

Provision Thick Disk on VSAN (Intentionally or By Accident)

There are several possible ways to provision a thick disk on VSAN.

• Possibility #1
• Define a thick VM Storage Policy
• Set the Object Space Reservation to 100%
• Use vSphere Web Client (cannot use vSphere C# Client)
• Select the thick VM storage policy
• Possibility #2
• Use vSphere C# Client
• Select “Thick Provision Lazy Zeroed” or “Thick Provision Eager Zeroed” on the disk type
• I don’t know what the actual impact on VSAN when selecting eager zero. In my test, the VM disk is still created correctly. I will do more research and post an update.
• Possibility #3
• P2V a physical server to VM
• By default, P2V uses thick provision on the disk
• Change to Destination Disk to thin provision by select Advanced, Destination layout, Type, Thin
• 
• 
• For VSAN 5.5, there is one more method, see here.

Change Thick Provisioned Disk to Thin on VSAN

Unfortunately, there is not a simple way to change a thick provisioned disk to thin on VSAN. Simply changing the VM storage policy on the disk has no impact.

In order to convert a thick disk to thin provisioned, do a storage migration of the disk to a SAN / NFS / local storage, then migrate back to the VSAN datastore. Make sure select the thin provision storage policy during the migration.

Brocade FC Switch FOS v7.2.0a WebTools Access in Windows Server 2012 R2 with IE 11

I got some errors (see at the end of the post) when setting up a brand new Brocade Fibre Channel switch running FOS v7.2.0a on a Windows Server 2012 R2 server with IE 11. The following instruction fixed the error.

• Install Oracle JRE 1.7.0 update 25 Windows x86 version
• According to its release note, FOS v7.2 is qualified and supported only with Oracle JRE 1.7.0 update 25.
• Install JRE Windows x86 version (32-bit), instead of Windows x64 version (64-bit) even Windows Server 2012 R2 is a 64-bit OS
• Launch “Java (32-bit)” in Control Panel
• Security tab, lower Security Level to Medium
• 
• (optional) Advanced tab, set “Perform certificate revocation checks on” to “Do not check”. This will speed up the “Verifying application” process if the server does not have the Internet access.
• 
• Launch Internet Explorer
• Click Tools, “Compatibility View settings” to add the Brocade switch IP address to the compatibility view list
• 
• 
• Enter the IP address of the Brocade switch in Internet Explorer
• 
• 
• 

The error messages I experienced and possible solutions

• “The version of Java plugin needed to run the application is not installed. The page from where the plugin can be downloaded will be opened in a new window.”
• Install the supported JRE version. see FOS release note for the supported JRE version
• Install the 32-bit version of JRE, instead of 64-bit version
• Verify Java Plug-In is enabled in IE
• Add the FC switch IP to IE’s compatibility list
• “Unable to launch the application” or “Unable to load resource: http://<switch-ip>/loc_res.jar
• Install the supported JRE version. See FOS release note for the supported JRE version
• “Application Blocked by Security Settings”
• Lower the Java Security to Medium in Java 1.7 Update 25. For the newer version of Java, add the FC switch URL to the Java Security Exception Site List.

Create CD/DVD ISO File in Windows 10

Windows 8 or later has the built-in feature to open / mount ISO files. However, creating an ISO file requires other tools. There are many free utilities available.

Today, I tried ISO Recorder v.3.1.3 64-bit. The last update on its web support says it supports Windows Vista and 7. In my test, it works in Windows 10 as well.

Create an ISO file

There is no icon or shortcut to launch ISO Recorder after the installation. To create an ISO file, right-click on the CD / DVD drive, and select “Create image from  CD/DVD”.

Mount an ISO file

Before installing ISO Recorder, Windows 10 will automatically mount the ISO to a virtual CD when double-clicking an ISO file. After installing ISO Recorder, double clicking an ISO file will launch ISO Recorder to write the image to a CD.

To mount the ISO file, right-click on the ISO file, and select “Open with” and “Windows Explorer”.

PS. I almost forget another free tool - ImgBurn. This was my go-to CD ISO creation and writing tool. The current version is v.2.5.8.0 released on June 16, 2013. This may still work in Windows 10, but I have not tried it yet.

Other free CD tools: MagicISO Virutal CD, WinISO 5.3, and CDBurnerXP.

Do Not Upgrade Dell Server with H730 and FD332-PERC Controller to VSAN 6.2

VMware released VSAN 6.2 on March 15, 2016. However, if your VSAN is running on a Dell server with H730 or FD332-PERC controller, do not upgrade to VSAN 6.2.

See KB2144614 for more information.

My IOPS Calculator

I look for an IOPS calculator for the EMC VNX2 5400 storage that I am working on. There are many available on the Internet. But none of them gives me exactly what I want. More frustrated, different calculators produce different results. So I decide to build one myself. Here is what I get.

My IOPS calculator concept:

• Based on EMC white paper “EMC VNX2 Unified Best Practices for Performance, October 2015”.
• Use EMC’s recommended RAID type configuration, IOPS, and formula.
• Use formula: Raw IOPS = Actual IOPS * Read % + Actual IOPS * Write % * RAID Penalty
  • Raw IOPS = Disk IOPS, Back-end IOPS
  • Actual IOPS = Host IOPS, Front-end IOPS
• Some calculators use different formula (see discussion). I can’t say they are wrong, but EMC’s formula makes more sense to me. I list all the ones I tested here
  • Result matches my calculator
    • http://www.yellow-bricks.com/2009/12/23/iops/
    • http://wintelguy.com/raidperf.pl
    • http://www.vclouds.nl/calculate-iops/
    • http://www.ryanfrantz.com/posts/calculating-disk-iops/
  • Result not match my calculator
    • http://thecloudcalculator.com/calculators/disk-raid-and-iops.html
    • http://www.myvmwareblog.com/2012/12/29/iops-calculator-2/
    • http://www.eksendata.com/araclar/iops/iopse.php
• There are two calculators in my spreadsheet
  • From disk qty, size, type, RAID type, and read/write percentage to get the actual usable storage and actual IOPS
  • From actual IOPS, disk size, type, RAID type, and read/write percentage to get the required disk qty

 

My IOPS Calculator Download (save the spreadsheet and open in Excel)

Fix “Deprecated VMFS volume(s) found on the host” in vSphere 6.x

An ESXi 6.x host shows an warning message “Deprecated VMFS volume(s) found on the host. Please consider upgrading volume(s) to the latest version.”

After verifying all the datastores mounted on the host are VMFS5, I restarted the management agent on the host. That cleared the warning.

This is a known issue on vSphere 6 (KB2109735).

VSAN Free Storage Catches

VSAN is a hot topic nowadays. Once it is set up, it’s easy to management and use. No more creating LUN and zoning.

We recently experienced some catches about its free available storage - at least we didn’t think about or were told before; or maybe our expectation to VSAN was too positive.

Our VSAN hardware disk configuration:

• 3 x Dell PowerEdge R730 nodes
• 2 x 400 GB SDD per node (372.61 GB is shown in VSAN Disk Management)
• 14 x 1 TB SATA per node (931.51 GB is shown in VSAN Disk Management)
• Two disk groups (7 SATA + 1 SSD) per node

Calculation of each node storage capacity (RAW):

931.51 x 14 = 13,041.14 GB = 12.73549 TB

Total storage capacity (RAW)

931.51 x 14 x 3 = 39,123.42 GB = 38.20646 TB

This calculation matches the storage capacity shown in the VSAN Cluster’s Summary.

We are adding more VMs to the VSAN. Once the free storage drops below about 12 TB (about one node’s RAW capacity), the VSAN health check starts showing critical alert “Limits Health - After 1 additional host failure” (KB2108743).

And the component resyncing starts more frequently.

My take away:

• I understand there is an overhead for VSAN (or any storage product) to offer the redundancy. But the way VSAN displaying the free storage is quite difference than the traditional SAN storage and it can be confused. The free storage shown in VSAN does not mean you should use it. Otherwise, the VMs may be down when a host is down or taken down for maintenance.
• The used storage in the Summary tab is the previsioned storage, not the actual space in use.
• The frequent resyncing component can potentially impact the overall VSAN storage performance.