SOLVED - RAID 5 problem - TOO slow - Pls help!

[pw44]

Hya,
after upgrading my hybrid (Asus M3N78-VM with AMD 955 and 2 GB), i've installed 4 drives:
1 with 320 GB for boot and system and 3 drives with 500 GB each and configured these 3 drives with mdadm making a RAID 5 array (/dev/md0).
My problem:
after transfering almost all my videos (avi, mkv, mpg, etc), when trying to play any of them, i get freezing during the playback, at the very beginning... then it accelerates the play and stops again.... during this freezings, the mouse also stops for a while.
The drive led indicator remains lit during this freezings.
I think that the array is simply too slow transfering the files... and that it's management drains all the resources.
Did anyone had such an experience or knows what could be happening?
It's the first time i'm trying to use mdadm and a RAID 5 array.
TIA

Paulo

[jimbodude]

I have never had performance issues of that magnitude while using mdadm - and I've been using it for years.  You may want to check the SMART status on those drives - if you're having read errors, then things will slow down to a crawl quickly.

[pw44]

Could it be related with rebuild or resync? Because it was build with mdadm, and after build, i transfered around 250 GB of files. After this initial transfer, the computer was shut down. The next day, i started lmce and imediately tryed to play movies. The computer slowed down up to freeze the mouse. I restarded the computer again, thinking something hanged. Tryed to start the other partition, with a kubuntu only. The same happened, slowing down up to freeze the mouse. I shutted it down again.
I suspect that after transfering files, the raid system needs a time to rebuild or resync. Am i right?

[jimbodude]

well, it's easy to check that theory:

Code: [Select]

mdadm --detail /dev/md0


[pw44]

Thx, i will try and give a feedback.
BTW, how do i create a wiki with my configuration, experience and workarounds?

[jimbodude]

...log in to wiki, click your username, type what you like.  Look at the source for some other peoples' to see how to tag it with categories and such.

[pw44]

The problem was RAID sync.. it took almost 1 day running (3 x 500 GB drives in a RAID 5), making file access very slow and freezing for a period of time.....
It now runs as it should...