Raimi war hier

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 currently does not run on MySQL 5.x due to a bug I reported and that was acknowledged several weeks ago. As cj pointed out correctly, my chances of getting that bug fixed would be higher if I was a paying customer. The problem is the above: What should I buy? Come on, MySQL - offer me something reasonably priced and we may be in business.

Oh, PS: We do not ship our application with MySQL nor do we ship the JDBC driver. Also, MySQL is the db engine for the "cheap" customers - the kind that won't pay 500 Euros per server per year just for a minor service hidden in their intranet.

And PPS: The same issue might occur for MaxDB. Some more demanding customers might pay for a MaxDB license if it came with some support. What shall I buy for them?

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 every disk access is suspended. The system becomes unusable.

We solved the problem by throwing out the controller replacing it with a Linux software raid. Suddenly the disks read and write happily at about 40MB/s. The fun part about this fact is that both the on-board SATA chip and the chips on the LSI controller are Sil 3114. It's the same thing, LSI just screwed it up.

We got rid of the controller several months back. If you are in the unlucky position of owning this device you might try flashing a new controller BIOS (which will be fun if your server (like ours) doesnt have a removable drive and doesnt run a Redmond-based OS) -- but this is just a straw.

The reason why I blog this now is that some of our customers have the same problem and others even buy new machines with this controller (Please Michael, stop selling them). When i started having performance problems i couldnt find negative reports on the net so this is my attempt to raise some noise.

Ich haenge ja schon eine weile in #maxdb auf freenode rum und unterhalte mich dort immer wieder nett mit cj, welcher mich dazu gebracht hat, diesen Blog bei planetmysql.de zu registrieren. Mal sehen, ob er angenommen und so gefiltert wird, dass ich die Welt nicht mit dem Privatkram belaste :)
Weiterhin bin ich noch unsicher, ob sich MySQL damit einen Gefallen tut, weil ich ja dann einen Grund habe, endlich mal alles zu schreiben, was ich von MySQL und MaxDB halte. Hier wisst schon...