[CentOS-virt] Xen Database vms

Fri Jan 15 17:13:02 UTC 2010
Grant McWilliams <grantmasterflash at gmail.com>

On Fri, Jan 15, 2010 at 8:58 AM, Raffaele Camarda <
raffaele.camarda at gmail.com> wrote:

> 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 at hotrodpc.com>
>
>

Don't use .img files for Databases! I've done the mysqlbench test on the
same machine with the same database with using LVM and img files and with
.img files I got within 5% of the Dom0 speed. When I moved the DomU to using
LVM I got within 1% of Dom0 speed. This is the one instance where there's a
definite advantage to LVM over img files.

Grant McWilliams
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