Low transferspeed from virtual machines?

[Mortis]

Hello

I run ESXi 4.1, with one fileserver, domain-controller, firewall, client and webserver.

The fileserver is used to store files for my home, but i get really low speeds, trough the network, often 11 MB/s, it can even be as low as 3 MB/s. The fileserver is based upon Windows Server 2008 R2. I have three datastores, each 2TB large (no raid-controller). Is this a problem that can be solved?

Greetings from Mortis

[a_p_]

Welcome to the Community,

ESXi does not do any disk caching for data security reasons. It fully relies on a disk/RAID controller with battery-buffered cache which provides write-back capability. If you are writing directly to the disks (no cache controller) the speed you see is expected.

André

[Mortis]

Thanks!

So what would be the best solution to get better network transferspeeds?

A RAID-controller? NAS?

Greetings from Mortis

[DSTAVERT]

There isn't usually one thing that solves all the problems. It usually involves a complete well thought out collection of hardware, software and an understanding of how to configure them to work together. A good hardware based RAID controller with write caching enabled (requires a battery backed cache module) will certainly help storage and perhaps by magnitudes. More smaller disks to achieve a particular storage volume rather than fewer larger disks helps. 

[Hoschi201110141]

Hi Mortis

Please tell me more about your Server / Storage / Network Configuration. The answer to your questions can not be Raidcontroller or NAS... it's a bit more behinde.

But i agree with a.p. you have maybe a Problem with your "Diskspeed". You can tray to seperate or distribute the VMguests.

By example:

I had an ESXi 3.5 at Home with 3 SATA Harddisks (no RAID)... because i had the routing-server and the filserver on the same Harddisk, i had sometimes problems with the Internetconnection while i copyed Data from / to the fileserver.

After i replaced one of the "normal" SATA Disks with an SSD Harddisk and moved all VMguests to it, i attached the Datastore-VMDK-Files from the fileserver wher now resides as onlyone on the SATA Disk.

After this reconfiguration i have the following winnings:

1. All my VMguest Running more stable becaus SSD is faster.

2. If there happens any swapping that can take down the performance... it happens on SSD

3. I get better performance from the fileserver because he is the onlyone that take use of the SATA Disks

I know SATA is not realy supported, specialy in ESXi 4.1... thats why i asked me: How can this guy have a 2 TB LUN?

Please tell me more about your configuration.

Regards

Hoschi

[Mortis]

Hello

I have the virtual machines spread across my three harddrives.

I also got storage spread across those drives, 300GB each for the fileserver.

Should i move all the storage for my fileserver to one single harddrive?

Specs:

Gigabyte GA-880GA-UD3H
AMD Phenom II X6 1055T
DDR3-PC10666 XMS3 16GB
WD Caviar GreenPower 2TB (three drives)

Antec Sonata III w/500W PSU

Intel Pro/1000 GT (two)

Greetings from Mortis

[Hoschi201110141]

Hi Mortis

OK, you have SATA Drives. It's fact that these Disk's are not realy realy fast.

My sugestion is not to move all VMDK-Files from the fileserver to one Disk.

What i mean is:

1. Buy an SSD Disk with SATA-Interface (realy fast)

2. If possible move all VM's to this Disk

This results in more performance for the VMguests itselfe. Because:

     - The Harddrive is fast

     - You have a higher I/O rate

     - You have lower latency

     When a VMguest is swapping someting to this disk... this will not slow you down

3. Use your three drives as Data-LUN's for your fileserver.

Because the fileserver then must not share the SATA Diskperformance with other VMguests.

I think if the Performance is then not what you expected..you can buy a Raidcontroller maybe with much cache

and build an RAID5. Or if you are rich... buy more SSD Disk's. Maybe an Software RAID from the filer can help you also.

Greetings

[DSTAVERT]

You have a fast processor and lots of RAM but without a caching RAID controller you will not get disk performance. A single OS has full access to the controller and the lack of cache is less noticeable.  ESXi is supporting multiple Operating systems and must give them equal access to the disk controller. Very basically, without caching, all write operations must complete before control is passed to the next. With caching, it isn't necessary to get acknowledgement from the controller that a write to the disk has been completed.

If you want performance you need a hardware based RAID controller with battery backed caching enabled.

[Schoerch]

Right. Use a hardware raid controller with cache and battery pack. Don't use a raid 5 with your three drives. This improve the perfromance. Use four drives as raid 5 ( for capacity n-1 ) or as raid 10 ( for speed n/2 ). You can also configure 2x raid 1 for balancing - one for VM OS and one for data store.

Not all raid controller can setup one array with more as one virtual drive (published to ESX OS).

[Mortis]

Hello

What would be a good and OK priced hardware RAID controller? I only have PCI-Express slots free, as i use the PCI slots for NIC´s.

I now have moved all my virtual machines to a single 7200rpm harddrive, so my three 2TB drives are free for the file server.

Greetings from Mortis