Re: [Xen-users] Xen - AoE benchmarks

[Markus Hochholdinger <Markus@xxxxxxxxxxxxxxxxx>]

Hi,

Am Dienstag, 1. Januar 2008 08:12 schrieb XenoCrateS:
> forgive me if this question has already been answered (i couldnt find any
> :( )..
> I am working on some xen based cluster where we were thinking of using AoE
> for storage management -rather than pinning a DomU's data partition to the
> same host (same stuff which everybody does)
> here comes my question:
> I have read in several places that AoE is sleek and fast for certain
> conditions,etc etc. But i couldnt find any real Xen-AoE combination (or
> atleast linux AoE) benchmarks in the internet.

also i read this many times. Well, i deployed my first Xen-Cluster in the 
beginning of 2006 and i choosed gnbd (over aoe, iscsi, enbd) for block device 
transport over the network.

In the last two weeks i'm re-evaluating. I'm comparing solutions which doesn't 
need any special hardware. I use gbit ethernet (sometimes bonded) and a lot 
of sata disks.

As far as i can tell i am very disappointed from AoE! It was a nightmare to 
setup aoe and vblade to get nearly the performance of gnbd! You have to use 
latest aoe (v63) module on the client side. You have to use latest vblade 
(18) on the server side, otherwise you will have poor performance with a high 
load. And you have to use jumbo frames (i'm using mtu 9000 with a direct link 
between two servers). With this setup i get the same throughput as with gnbd. 
But with aoe the cpu load is much higher. I also have to note here that older 
vblade versions dropped extremly performance if you exported more than one 
block devices with vblade. With 100 lvs exported with older vblade version i 
couldn't read more than 600 KB/s (yes, KB!!!!) from ONE aoe device at a time! 
The system load of my vblade server went up to over 20 (2 Intel Quad Core 
2.66 GHz).

The real world test, a running domU, i can read about 130 MB/s with gnbd and 
with aoe. With aoe, the load of the (vblade) server is much higher than with 
gnbd. So i could live with this. But i can only write about 30 MB/s with aoe 
in contrast to gnbd where i can write about 80 MB/s. If i turn on O_SYNC 
within vblade, write performance goes under 10 MB/s.

So with this results i can't change my setups to aoe! The performance loss 
would be to much!

Because of what i read, i thought aoe should perform better than iscsi. For 
now i will test this myself. I get the feeling that people are using the 
technique they get first to work!?


-- 
greetings

eMHa

Attachment: pgp8pORxbEDnP.pgp
Description: PGP signature

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users