I was hitting the same problem last days so i went through some test, the configuration you suggest is quite nice and according to my result yun anticipated me on the problem doing my next step ;).
basicly i was wondering using MySQL Cluster and a Cluster MySQL for some different services. Setting the point that mysql cluster was taken in account for availability specs more than for its performance.
That said here some spec data:
hp/ibm dual quadcore with SAS RAID and 8GB of RAM. (for dom0) OS: Centos 5.3 Virtualization: xen
for real server no SAS but SATA RAID and 4GB of RAM
I got 4 of the former and 2 of the latter. All domus where on .img files.
Used sysbench for testing
i tested: mysql cluster on domUs, mysql on domu and mysql on real server
I got real pour performance with mysql cluster on domus no data for that, but no optimiziation was done.
Moreover consider that no optimizatino was done for none of the configurations.
No conclusion at all, more serious efforts can be done for getting the best from each donfiguration, so just get this datas as a non production test, which is what it is.
Here some numbers hope they are usefull:
***************************Mysql cluster on real server (SATA + 4GB) ******************** sysbench --num-threads=4 --max-requests=20000 --test=oltp --mysql-db=sbtest --mysql-user=test --mysql-password=*********** --mysql-host=************** --mysql-port=********* --mysql-table-engine=ndbcluster --oltp-test-mode=complex run
OLTP test statistics: queries performed: read: 280000 write: 100000 other: 40000 total: 420000 transactions: 20000 (440.95 per sec.) deadlocks: 0 (0.00 per sec.) read/write requests: 380000 (8378.12 per sec.) other operations: 40000 (881.91 per sec.)
Test execution summary: total time: 45.3563s total number of events: 20000 total time taken by event execution: 181.2726 per-request statistics: min: 5.72ms avg: 9.06ms max: 154.81ms approx. 95 percentile: 10.30ms
Threads fairness: events (avg/stddev): 5000.0000/2.74 execution time (avg/stddev): 45.3182/0.00
******************** Plain Mysql on xen domu ************************* OLTP test statistics: queries performed: read: 280000 write: 100000 other: 40000 total: 420000 transactions: 20000 (368.68 per sec.) deadlocks: 0 (0.00 per sec.) read/write requests: 380000 (7004.93 per sec.) other operations: 40000 (737.36 per sec.)
Test execution summary: total time: 54.2475s total number of events: 20000 total time taken by event execution: 216.8328 per-request statistics: min: 6.35ms avg: 10.84ms max: 263.48ms approx. 95 percentile: 11.14ms
Threads fairness: events (avg/stddev): 5000.0000/2.45 execution time (avg/stddev): 54.2082/0.00
******************* Finally mysql on real server (SATA + 4GB) *************** OLTP test statistics: queries performed: read: 280000 write: 100000 other: 40000 total: 420000 transactions: 20000 (467.17 per sec.) deadlocks: 0 (0.00 per sec.) read/write requests: 380000 (8876.18 per sec.) other operations: 40000 (934.33 per sec.)
Test execution summary: total time: 42.8112s total number of events: 20000 total time taken by event execution: 171.0977 per-request statistics: min: 5.67ms avg: 8.55ms max: 133.64ms approx. 95 percentile: 9.84ms
Threads fairness: events (avg/stddev): 5000.0000/2.55 execution time (avg/stddev): 42.7744/0.00
2010/1/15 compdoc compdoc@hotrodpc.com
-----Original Message----- Fhttp://www.liveleak.com/view?i=375_1263347833rom: centos-virt-bounces@centos.org [mailto:centos-virt-bounces@centos.org] On Behalf Of Ben M. Sent: Friday, January 15, 2010 8:56 AM To: Discussion about the virtualization on CentOS Subject: Re: [CentOS-virt] Xen Database vms
Neil:
What if it were the only "real" active vm? I know that might sound a bit of a waste, but I am really enjoying the backup and duplication abilities of running in a Xen hypervisor as well as its other features. It seems to be saving me a lot of time in production settings. And there is also a comfort level in uniformity on a LAN.
Would there still be a significant hit on resource performance by the hypervisor if running that database server alone in it, or alongside a few rarely used, lightweight or spurious vms? I am talking about the database activities running during the biz day and backups, batches and other maintenance in the off hours. Nothing urgent here, just trying to plan out the future, mull over the possibilities and where to head.
- Ben
-----Original Message-----
I think it could work well. Having a server in a vm makes it more portable.
Many of my servers and services are running in vms on two centos 5.4 servers: openfiler, efw firewall, trixbox 2.8, SME Server (in server mode for email and spamassassin), windows 2003 server, windows 2008 server, windows 7, and others that aren't running.
I would suggest:
If there are a lot of temp files or disk access to the OS, install the vm OS on a block device rather than to a file. The storage should be on a local block device as well.
If there's a lot of lan traffic to/from the other vms, install a 3rd ethernet card in the server that is only used for db traffic.
I also use a virtual network that the vms can use to reach each other. This is basically a private internal lan running across the host machine's buses, rather than through your network switch.
I get native performance with my set up...
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