Local datastore copy performance

[usy]

Hello,

I am trying to copy vmdk file from one datastore (first physical drive) to another datastore (second physical drive on the same machine) using vSphere Clinet Datastore Browser. Performance is horrible: about 3000 KBps. Is this behaviour normal? I'm getting way better speed while copying the file over the http datastore browser through LAN to my laptop. Write/Read operations in running VM's are also ok.

VMs are all shutdown, ESXi is in maintenance mode. The server is a HP Proliant ML150 G6.

Thanks,

usy

[idle-jam · Accepted solution]

does the local disks has any battery backed write cache controller?

[usy]

No, both disks are on a Smart Array P410 controller without battery-backed write cache.

[AndreTheGiant]

Without battery you cannot have a write back caching policy... so write performance will be "bad" (they depends on the physical disks  performance).

Andre

[usy]

I don't think that this is the case, because when I copy files through LAN to a VM or between VM's I'm getting about 9 MB/s. When I copy a file in a VM ~30 MB/s, so the only lack of performance (3 MB/s) is when manipulating files directly in datastores.

[DSTAVERT]

Both Andre and idle-jam have both seen this same question posted several hundred times. You may disagree but I would suggest that you listen. Do a search in the forums.

[usy]

OK, sorry for my lack of faith. Did some seraching, gonna upgrade the controller with a BBWC and see how it goes. Thanks for the answers.

[DSTAVERT]

Depending on the environment there can be as much as a 10 fold increase. If your controller doesn't already have RAM installed, select the 512MB. Good luck and let us know how it goes.

[Mordecai2011101]

Hello
DSTAVERT
usy
AndreTheGiant
idle-jam

I have a similar issue as usy. ESX 4.1 is experiencing write  latencies to disk.

Virtual Disk Write Latency shot up to 2,474ms and Disk Write Rate shot up to 1060 KBps - just running Windows updates on a Server 2008 VM.

A Potential Lab Rig

  - HP proliant ML150 G6 Server
   - HP Smart Array B110i SATA RAID Controller (RAID 0,1,10)
   - 1 250 GB SATA Drive housing ESX 4.1
   - 1 TB SATA Drive for the Data Store (I plan on mirroring or RAID 5 when disk writes improve)

I recently placed an order to get the HP Smart Array P410 /512 FBWC 2-ports Int PCIe x8 SAS Controller"
without the Battery, although the option for the Battery is available.  I saw this post after the fact I ordered and wanted to find out if it matters ?

Is it preferrable to get the Battery Backed Write cache controller instead of the Flash Backed Write Controller for ESX 4.1 ?

I asked HP support and they told me " Battery is used to migrate, expand, or for power outages suchas if
failure occurred in the Array, then data is written by battery from cache to  disk. Without the Battery all data on cache module would be deleted."

Not sure what to change in my order--Should I add the battery to the HP Smart Array P410 /512 FBWC or cancel it

and go with the P410 BBWC/512 MB ?     http://h18000.www1.hp.com/products/quickspecs/13201_div/13201_div.html