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Expert
Expert

moving VM Disks to new SCSI ID

I currently have a bunch of fisks on the same SCSI(0) ID

like

Disk 0 SCSI(0:0)

Disk 1 SCSI(0:1)

DISK2 SCSI(0:2)

DISK3 SCSI(0:3)

etc....

noticing lot of write/read latency

Will it imprive performance if I move some disk off to its own SCSI ID?

SCSI(1:0)

SCSI (2:0)

etc....

how would i do that?

This is windows 2016 server and I want to keep same drive letters

6 Replies
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VMware Employee
VMware Employee

That would give each virtual disk it's own virtual controller, meaning you'd have more queues in the guest OS.

What type of controller is in your VM settings? PVSCSI?

Will multiple virtual controllers solve your issue? Not if the issue is with anything physical, so rule out everything in that space first.

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Immortal
Immortal

> Will it imprive performance if I move some disk off to its own SCSI ID?

Yes it will improve the performance - but dont expect radical improvements.

Changing the SCSI ID can change driveletters - which again may result in not starting services on next reboot.

So dont change all at once and expect to assign new driveletters manually after next reboot.

The change can be done via the UI.

If you do it by editing the vmx you need to add scsi-controllers manually.

Do you need support with a recovery problem ? - call me via skype "sanbarrow"
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Expert
Expert

yes its pvscsi.

i have 8 disks on the same scsi0 controller

I am seeing write/read latency

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VMware Employee
VMware Employee

As per my first reply, you have a bunch of physical things to check before thinking about changing VM disk controllers.

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Expert
Expert

is it normal to see read/write latency on virtual disks?

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User Moderator
User Moderator

As Scott mentioned, if the underlying physical infrastructure is not able to process the data fast enough, you will see such latency.

André

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