Optimize Your Server

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Optimize Your Server

There are a few changes you can make to your Cobalt RAQ to optimize it's performance. This article covers both software and hardware changes you can make to maximize your server's performance.

Optimizing bdflush

The bdflush parameters adjust the overall disk performance of the Linux kernel. The parameters below optimize the system to fill the buffers before emptying them to disk. This allows the operating system to perform more work instead of emptying the buffers on a more frequent basis.

You can view the current bdflush settngs by using this command:

cat /proc/sys/vm/bdflush

Login as root and issue the following command:

echo "100 1200 128 512 15 5000 500 1884 2">/proc/sys/vm/bdflush

The default bdflush for the RAQ 550 OS is:

30 500 0 0 500 3000 60 20 0

Hard Disk Optimization

You can also optimize the hard disk parameters using hdparm. The RAQ 4 does support ATA66 hard disks if you program the controller to use it. However I do not recommend changing this setting without replacing the hard drive cables to the newer ATA100 cables. This can be done using hdparm. You should run the system in single user mode using a terminal before changing any settings using hdparm or you risk corrupting your hard disk!

If you enter: hdparm -iv /dev/hda

You will see the current settings for the first hard disk. Use hdparm -iv /dev/hdc for the second hard disk if you have it installed.

Checking the status of the hard disk:

You can check the status of the ide hard disks by using: /usr/local/sbin/ide-smart /dev/hda /usr/local/sbin/ide-smart /dev/hdc

If the system reports Failed for any parameter, it's time to start getting your data off the hard disk! I use the following in my crontab to monitor my hard disks:

00 07 * * * /usr/local/sbin/ide-smart /dev/hda|grep Failed 00 07 * * * /usr/local/sbin/ide-smart /dev/hdc|grep Failed

Hardware Optimizations

These optimizations aren't free but they do make a signficant difference in the overall performance of your Cobalt RAQ server.

Increase your RAM beyond 512MB

You can install up to 1 GB of ram in the RAQ 4. However only 900 MB will be usable due to the way memory is mapped within the RAQ. To do this, install (2) 512MB PC100 or 133 sims and you are all set. You can purchase them at RAQWare - http://store.raqware.com/product_info.php?products_id=44 I have been sucessful in using a 512MB/128MB sims = 640MB, 512MB/256MB sims = 768MB as well. If you use more than 512MB you should be aware that the motherboard cache cannot cache any ram beyond 512MB. However the ram is over 1,000 times faster than using your swap space on your hard disk.

Replace Your CPU

Also, RAQWare sells a replacement cpu (K6-III+/450ACZ) for the RAQ4 which signficantly improves performance. See http://store.raqware.com/product_info.php?products_id=170 The new CPU adds a 256 KB cache on the chip that operates at 450 MHz and moves the existing 512 KB cache as a 3rd level cache. Make sure you use the heat sink grease when you install your new cpu for maximum heat transfer. Also, the new cpu runs cooler! Also, the temperature limit is higher 85C vs 65C for the original CPU The cache on the CPU is used for all ram. So this offsets the problem above with using more than 512MB of ram.

I have seen a performance increase of over 33% after I installed the replacement cpu.

From the kernel log with the K6-III cpu installed:

Jan 8 17:51:25 srv02 kernel: CPU: L1 I Cache: 32K (32 bytes/line), D cache 32K (32 bytes/line)

Jan 8 17:51:25 srv02 kernel: CPU: L2 Cache: 256K (32 bytes/line)

Jan 8 17:51:25 srv02 kernel: CPU: AMD-K6(tm)-III Processor stepping 00

Here's the kernel log with the original K6-II cpu:

Dec 20 22:37:11 srv02 kernel: CPU: L1 I Cache: 32K (32 bytes/line), D cache 32K (32 bytes/line)

Dec 20 22:37:11 srv02 kernel: CPU: AMD-K6(tm) 3D processor stepping 0c

--ChrisD 18:12, 15 May 2005 (UTC)

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