Poor performance inside VM and with Shared Folders

[Knappe]

Hello,

I wanted to use VB as a VM on a Ubuntu 10.10 host for a guest MS Server 2008R2 (server machine).

For this maschine
- Asus Board M4A87TD with AMD Phenon II X6 1055 T
- 16 GB RAM
- 4x WD ATA WDC WD 1002FAEX-0023A6 (each 1 TB) put into 2x Raid-0
- Virtualbox Version 4.0.2 r 69518
host : Ubuntu 10.10
guest :
- Server 2008 R2 (Windows 2008 64-bit)
- 4 GB RAM
- SATA-Controller (SATA-0)
- VDI = 200 GB (dynamic)
I tested the performance by copying a 44 GB File (also a VDI-File) in several ways and the VB was incredible slow :

Code: Select all

Ubtuntu  (Reference) ---> RAID 1   to RAID 2     => min. 226,6 MB/s | max. 234 MB/s | av. ±  228 MB/s
Ubuntu               ---> RAID 2   to RAID 1     => min. 186,0 MB/s | max. 199 MB/s | av.  ± 192 MB/s    (*1
VB, Test 1           ---> SF 1       to SF 2     => min.  53,0 MB/s | max. 123 MB/s | av. ±  59-60 MB/s  (*2
    Test 2           ---> SF 2       to SF 1     => min.  31,0 MB/s | max. 100 MB/s | av. ±  40-60 MB /s (*2
    Test 3           ---> SF 1       to  C:\temp => min.  69,7 MB/s | max. 232 MB/s | av. ±  70-90 MB/s  (*3
    Test 4           ---> C:\temp to  SF 1       => min.  43,0 MB/s | max.  77 MB/s | av. ±  70-90 MB/s  (*3
    Test 5           ---> C:\temp to  C:\temp    => min.  69,7 MB/s | max. 232 MB/s | av. ±  70-90 MB/s 

SF 1 = Shared Folder = RAID 1, 
SF 2 = Shared Folder = RAID 2

*1 is lower because another VM was running on this RAID (without any special traffic).
*2 copy inside VM (via Server 2008 R2)
*3 copy from Shared Folder into VM or vice versa
Because of config = "dynamic" I copied the above file 2 times before into the VM. After, the total size was > 105 GB, then the tests started.

Can anybody confirm these "very bad" results ?
Maybe anybody have a solution ?

[uli100]

Hi Knappe,

...
Can anybody confirm these "very bad" results ?

unfortunately, I can confirm that the shared folder performance is bad within windows guests. I'm using it to copy small files to and from a windows xp vm. It takes time to access the folder and the files from within the guest system. I try to avoid shared folders whenever possible.

Best regards, Uli.

[Knappe]

Hi @uli100,

I can confirm that the shared folder performance

thx, but look to Test 5, same "slow motion" inside the VM

[fixedwheel]

Hi uli100

It takes time to access the folder

did you modify the guests lmhosts file? => http://www.virtualbox.org/manual/ch12.html#id375947

[Knappe]

did you modify the guests lmhosts file?

Yes - nothing changed.

I found a thread, discussion this (for older versions) --> http://www.virtualbox.org/ticket/1728
But it doesn´t realy help ...

[fixedwheel]

Yes - nothing changed.

AFAIK lmhosts is a cure for long think time when accessing shared folder, not for speeding up transfer rate


hmm... what host filesystem is your RAID?

[Custodian_Carl]

I'm currently using a Bridged Network Adapter and accessing Windows Shares from my guest os, Ubuntu 10.10 on host Windows 7 64. I'm experiencing ~14MB/s transfer rates on an expanding VM partition, VM extension is .vdi. I'm curious if this is normal for an expanding VM partition?

[mpack]

Yes - nothing changed.

AFAIK lmhosts is a cure for long think time when accessing shared folder, not for speeding up transfer rate

Yes.

I'm not sure that the following has been specifically mentioned in the discussion so far, so...

When it comes to inproving transfer rates many, including myself, have found that "real" network shared folders give MUCH better performance than VirtualBox GA shared folders. No idea why, maybe it was a short term bug that was since fixed, but still... a lot of expensive devteams in big outfits have spent a lot of time getting real network shares to work at an adequate speed, so we may as well take advantage of that IMHO.

Allegedly, using VirtIO-net as the NIC type, with of course VirtIO drivers in the guest gives even better performance. I say allegedly because I didn't actually measure it. I can confirm that performance was certainly not worse. You need to hunt down the appropriate drivers for your guest OS (VirtIO originated on Linux, but Windows drivers are available).