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vmware cloning and Synology CPU I/O Wait

Wasim Shaikh
Wasim Shaikh asked
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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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Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
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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Commented:
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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Commented:
Both the volumes has VAAI enabled.
am using NFS is for storing ISO files.
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
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?
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Commented:
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.
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
You can increase performance, by installing 2 x SSDS for read and write cache.
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Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
Correct, Synology does not enables VAAI (adv feature) unless I don't select Thin Provisioning.
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Commented:
By changing the LUN type from thin to block level, I was able to reduce the I/O Wait.

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