MySQL performance concern

[Matthew Seaman]

On 02/10/2010 08:06:52, Rumen Telbizov wrote:
> Hello everyone,
> 
> I am experimenting with MySQL running on FreeBSD and comparing with another
> (older) setup running on a Linux box.
> My results show that performance on Linux is significantly better than
> FreeBSD although the hardware is weaker.
> I'd appreciate your comments and ideas.
> 
> Here's the setup:
> 
> 1) FreeBSD 8.1-STABLE amd64 (Tue Sep 14 15:29:22 PDT 2010) running on a
> SuperMicro machine with 2 x Dual Core
> Xeon E5502 1.87Ghz ; 4 x SAS 15K in RAID10 setup under ZFS (two mirrored
> pairs) and 2 x SSD X25-E partitioned
> for: 8G for ZIL and the rest for L2ARC; 16G ram with 8 of them given to
> mysql and tons of free.
> 
> 2) Linux Gentoo with 3 SATA disks in hardware RAID5 with similar
> cpu/motherboard and same memory size.
> 
> The sole application that runs is a python script which inserts a batch of
> lines at a time. Only myisam is used as a format.
> Here's the problem: On the Linux box it manages to push around
> *5800*inserts/second while on the FreeBSD box
> it's only *4000/*second.
> 
> MySQL version is 5.1.51
> 
> During this load the disk subsystem on FreeBSD is pretty much idle (both the
> SSDs and the SAS disks). CPU utilization
> contributed to mysqld is only around 30%. So I am clearly heavily
> under-utilizing the hardware.
> Linuxthreads support for 64bit architectures is not available so I couldn't
> try that but aside from that I tried recompiling
> mysql with all the different Makefile options available without any effect.
> Changing the recordsize in zfs to 8K doesn't make any difference.
> Tried percona binary without any luck.
> 
> Let me know what additional information would be useful and I'll provide it
> here.
> 
> Thank you in advance for your comments and suggestions.

Um... a fairly obvious point, but have you tuned the mysql configuration
appropriately on both machines?  I'd guess you have, but you didn't
mention it.  As I recall, the default configuration you get out of the
box with mysql is suitable for a machine with something like 64MB RAM.
Not at all appropriate nowadays where dedicated DB server hardware would
be more likely to have 64*G*B than 64*M*B...

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW

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