While one of our main servers is checking its root filesystem I can take the time to write about MySQL licensing.

I think that the price model is not suitable for ISVs like the company I work for. Prices begin at about 500 Euros per server and year which would allow use to report two bugs. Since we develop software that works on MySQL (and MaxDB and other relational RDBMS) this model does't seem to be applicable to us: We do not run a server for any customer or ourselves, we just have some development environments. Also, we do not only run one version of the software but four (Mysql 4.0, 4.1, 5.0, 5.1) just to make sure our application works with all of them (customers tend do have either ancient MySQL versions or brand new ones). So shall we buy four cheap licenses? Four expensive ones for unlimited bug reporting? One for unlimited bug reporting?

This subject is rather hot for me because our application …

This is a general warning: Do not use megaraid SATA RAID controllers (LSI Logic / Symbios Logic PowerEdge Expandable RAID Controller 4 (rev 01), also rebranded and sold by major manufacturers).

We had a machine with both Linux 2.4 and 2.6 running (various versions), Seagate and WDC disks, tried to tune software and BIOS parameters. Nothing helped. This is what we took out of order:

megaraid cmm: 2.20.2.5 (Release Date: Fri Jan 21 00:01:03 EST 2005)
megaraid: 2.20.4.5 (Release Date: Thu Feb 03 12:27:22 EST 2005)
megaraid: fw version:[713G] bios version:[G117]
scsi0 : LSI Logic MegaRAID driver

This controller does not deliver more than 6MB/s when reading from a mirrored RAID. Sustained write performance is something like 4MB/s, but that's not the worst part: You can write very quickly to it until the on-board cache is full (64MB). While this cache is being flushed the host system comes to a complete halt since …