VMware Cloud Community
jordendrew
Enthusiast
Enthusiast
Jump to solution

Transferring VM from one host to another extremely slow

So, I've been going through a lot of posts on this issue, and I still have not found a solution for this. We have a Vsphere 5.5 server that is running our backup server for our customers. I have an 8 TB thick provisioned vmdk. We have recently purchased a new server which we have installed vshphere 6.0 on. I have joined the two hosts to a vcenter server. I went to do a cold migration of the virtual machine and data from the old host to the new host. The problem is that I am only getting a max of 15 MBps but averaging 10. I have a 1 gbps switch with CAT 6a cables. vcenter-transfer.JPG

Tags (2)
0 Kudos
1 Solution

Accepted Solutions
a_p_
Leadership
Leadership
Jump to solution

Are the disks connected to a controller which has a write-back cache option? Without write cache, controllers will usually operate in write-trough mode which would likely explain the low throughput you see.

André

View solution in original post

7 Replies
jpsider
Expert
Expert
Jump to solution

Are the esx hosts using shared storage? or are you migrating the host and datastore? Is that necessary?

If you are migrating the data store, what types of disks do you have?

0 Kudos
BoneTrader
Enthusiast
Enthusiast
Jump to solution

what kind of storage Setup do you use?

0 Kudos
jordendrew
Enthusiast
Enthusiast
Jump to solution

Each host has its own storage. I'm migrating everything over because we maxed out the storage on that server. The disks we are using are SATA spinning disks 10,000 RPM i believe.

0 Kudos
a_p_
Leadership
Leadership
Jump to solution

Are the disks connected to a controller which has a write-back cache option? Without write cache, controllers will usually operate in write-trough mode which would likely explain the low throughput you see.

André

jordendrew
Enthusiast
Enthusiast
Jump to solution

Yes, it does.

0 Kudos
jordendrew
Enthusiast
Enthusiast
Jump to solution

After looking at some logs while transferring, we are seeing some errors about a USB device. the only usb device we have plugged in is our SD card module which ESXi is installed on a SD card. Would installing esxi on a SD card cause some issues with trasferring the VM from one host to another? anyway to bi-pass the SD card and go directly to the new datastore?

0 Kudos
jordendrew
Enthusiast
Enthusiast
Jump to solution

a.p. wrote:

Are the disks connected to a controller which has a write-back cache option? Without write cache, controllers will usually operate in write-trough mode which would likely explain the low throughput you see.

André

So After hours of trying things, we decided to look at the actual settings for the raid card configuration. Turned out the cache mode was set to write-through. we changed it to write-back and the speeds are now about 100MB/sec which sounds about right. Thanks for the suggestion!

0 Kudos