ESXi 5.5 very slow read/write on local datastore from a VM (write cache already enabled!)

[beistrich]

Hello!

I currently have a problem on a new installation with ESXi 5.5 and local storage.

The server is configured with 8 disks and RAID 5 (1 hot spare)

Write cache with bbu is enabled (LSI controller)

I recognized the problem when configuring Veeam Backup to a NAS, which is very slow (about 200kbit/s).

The problem can be reproduced when downloading files (iso e.g) FROM the local datastore from a VM on the host (to a local directory of the VM)!

Copying TO the datastore seems to be ok.

But, downloading FROM the local datastore from physical machine (over network) seems also be ok!

Copying Files to/from a VM on the host over network also produces no performance issues!

So I think that it is not a Veeam problem, because the problem can be reproduced by using the datastore browser.

Anybody has a solution for this problem?

I would be very happy to find a solution!

br

Christoph

[Linjo]

You should not base any performance measurment on the datastore browser, it has a lot of overhead and is not optimized for performance.

Use something like iometer instead.

// Linjo

[admin]

Hello,

Downloading from the data store cannot actually give you a performance benchmark, you may need to try with other options.

-- Avinash

[beistrich]

Ok, I agree!

How can I measure the performance by another way?

[Linjo]

Use something like iometer instead.

// Linjo