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vmware cloning and Synology CPU I/O Wait

Posted on 2014-12-29
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Last Modified: 2015-01-11
Hello Experts,

Let me show you waht I have in LAB.
2 ESXi host, Synology NAS,

Storage:
A DiskGroup with 2x2TB on top of this a single Volume  in RAID-0.
2 x iSCSI LUN (file based): LUN-1 and LUN-2

1x1TB on which a single SHR Volume
1 x iSCSI LUN (file based): LUN-3

Host-A is configured with 2 vSwitch:
Switch1(vmnic0): VMNetwork and Mgmt
Switch2(vmnic3): Storage

Host-B is configured with 2 vSwitch:
Switch1(vmnic0): VMNetwork and Mgmt
Switch2(vmnic5): Storage

All datastore are configured with multiple paths
pathsLUN-3
CASE-1
I have a vm template on LUN-3 and when used to deploy vm from it on LUN-2 or LUN-1 it gets slow gradually.
When checked the under resource monitor
CPU IOWaitR/W IOPSTransfer Rate per volume
CASE-2
If same thing is performed in reverse i.e., template on LUN-1 or LUN-2 deployed on LUN-3 there is better results.
CPU IOWait 2IOPSTransfer rate
What can be the reason for this?

Thanks for the time.
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Question by:Vaseem Mohammed
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LVL 117
ID: 40522101
Have you enabled Jumbo Frames, and configured multi path correctly for iSCSI ?

HOW TO: Enable Jumbo Frames on a VMware vSphere Hypervisor (ESXi 5.0) host server using the VMware vSphere Client

HOW TO: Add an iSCSI Software Adaptor and Create an iSCSI Multipath Network in VMware vSphere Hypervisor ESXi 5.0

Have you tried NFS, and are there any VAAI plugins available for the Synology NAS ?
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LVL 12

Author Comment

by:Vaseem Mohammed
ID: 40522190
Jumbo Frames are enabled on both ends. storage as well as on hosts.
Multipath is configured by using 2 different vswitches and not as showed in your article with single switch and 2 vmk PG. is this approach is incorrect?
Host NetworksPort Bindings
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LVL 12

Author Comment

by:Vaseem Mohammed
ID: 40522192
Both the volumes has VAAI enabled.
am using NFS is for storing ISO files.
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LVL 117
ID: 40522253
Best practice and recommend is as per my EE Article for multipath.

NFS can provide less overhead, than iSCSI.

Why Synology NAS is it, and how many disk bays?
0
 
LVL 12

Author Comment

by:Vaseem Mohammed
ID: 40522281
Lacking on switch ports, so can't go with recommendations.
Yes, I noted your point from previous post about NFS.
I am moving vms right now and will try using block iSCSI.
Don't know why, may be I like how it sounds iSCSI :-))
Truth is, got this new DS1515 so taking it left and right, coz I need to know how fast it can perform.. at present only 3 HDD are in place.
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LVL 117
ID: 40522335
You can increase performance, by installing 2 x SSDS for read and write cache.
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Accepted Solution

by:
Vaseem Mohammed earned 0 total points
ID: 40526134
I delete the previous LUN's which were "Thin Provisioning" enabled and VAAI supported.
Created a single LUN (Block level) without VAAI and Thin Provisioning capabilities.
LUNThere is no more high I/O Wait, may be coz of Thin Provisioning Synology CPU has to wait for the Block Zeroing and this was adding up to I/O wait.IO Wait
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LVL 117

Assisted Solution

by:Andrew Hancock (VMware vExpert / EE MVE)
Andrew Hancock (VMware vExpert / EE MVE) earned 250 total points
ID: 40526160
I would not create thin provision LUNs.
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LVL 12

Author Comment

by:Vaseem Mohammed
ID: 40526163
Correct, Synology does not enables VAAI (adv feature) unless I don't select Thin Provisioning.
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LVL 12

Author Closing Comment

by:Vaseem Mohammed
ID: 40542874
By changing the LUN type from thin to block level, I was able to reduce the I/O Wait.
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