CentOS

I just finished installing a fresh copy of CentOS 5 from DVD on to a Lenovo TS-430 Thinkserver using the exact steps outlined in this wiki:

http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5

No problems were encountered along the way, but when I boot up I still see messages that say my md2 raid device is not clean and that background reconstruction is going to take place. The system then boots up, I can log in, but overall system performance seems slow and very very jerky. It will seemingly lock up for a few seconds at a time, unfreeze, and this goes back and forth. Besides this the system seems to be running stable. No error messages or anything unusual besides this weird performance issue which is system wide; all processes seem to be delayed/frozen simultaneously. I am not sure what to think about this or possibly work around it. I've applied a batch of updates from the repositories but no improvements were seen.

Suggestions? I am considering purchasing a hardware RAID controller suspecting it to be the cause of the slowness but at the same time I remembered that just before trying CentOS I installed Ubuntu 10.04 64-bit and it ran very smooth and quick with no problems off the same general software RAID setup (I believe both OS's rely on mdadm to actually control/host the RAID array). So before spending $200+ on something decent I'd just like to rule out any other possibilities that might cause sluggish behavior like this? Could it possibly be the GUI?

If the RAID is rebuilding it will adversely effect performance. The question on my mind is [b]why[/b] should it be rebuilding after a fresh install? Possible hardware issues? How's the SMART status? Any errors in the logs?

There's no question that a good hardware RAID will give better performance. You will have to make your own evaluation of cost/performance trade-offs as that's dependent on your budget flexibility and requirements.

I am having thoughts that these weird hiccups are not being caused by the RAID array but I can't say that for certain just yet. I've got some time to kill so what I think I'm going to do is reinstall the OS one more time, but in a non-RAID setup using just one drive as a test to see if it runs any better or not. I have a bad feeling that it won't which leads me to worry that I'm going to have to figure out some other much more difficult to diagnose issue.

There should be no hardware problems with this system at all. All the parts are brand new and as mentioned this was not an issue that I had to worry about when I tried to run with Ubuntu. I'll report back tomorrow with the results of the non-RAID install. In the mean time it may not hurt to speculate what might cause the system to freeze every three seconds. To give you an idea of what I'm talking about, imagine you're typing in your password after the screensaver's locked the account. The dots don't appear in sync with the keystrokes; in fact it's like the keystrokes queue up and then appear in bunches. Backspacing happens the same way. This even happens when I switch to a virtual terminal (CTRL-ALT-F2) and try to type stuff in that environment.

Update: I ran the command:

cat /proc/mdstat

And it produced a result which basically said the root partition was busy resyncing with about 10 percent completed so far and an ETA of being finished of some number over 4000. So... it seemed to be working. But I'm planing to go hardware raid now so I didn't really care to keep this from being interrupted; I plan to rebuild the system with a controller later. One thing that I did do that made me feel a lot better about the stability of the system was disconnect the secondary SATA drive and leave the primary attached and started back up, so I would essentially be running with just one drive. Everything was much snappier after that, so it was clearly the software array that was causing the jittery behavior and more the reason to invest in a controller card.

I have my eye on an Adaptec card, this one in particular:

http://www.newegg.com/Product/Product.aspx?Item=N82E16816103102

I was wondering if anybody has experience with these cards, thoughts, etc. And if anybody knows of a good guide that talks in detail about how to install these things I'd love to see it. I wanna make sure I know what I'm doing when I set this up (first time I've dealth with a hardware raid controller before).

Thanks in advanced!

Just my two cents worth:

If your budget permits, find a RAID card that has a BBU. This is a must for database servers. Its been quite some time now since I have visited their(Adaptec) site and to my surprise they are now offering Zero-Maintenance Cache Protection which replaces the BBU. BBU and ZMCP makes it possible for data on the cache to be written on to the drives even in the event of power failure.