How many RAIDs should i use!?
 

I posted this in the newbie form but got no answers. I no its not good reposting things, but its maybe to much for a newbie form, just wont your opinions guys...

Hi guys...

I have a system that i am setting up that will be a file server and a Internet gateway.

Specs...

P 400MHz
128 MB Ram (will be 512)
Two 3 GB HDD in RAID 1
Redhat 9


The first time i set up the RAID i made one RAID set up that mirrored everything from /. there was no separate boot or swap partitions.

The second time i set up 3 different RAIDs one for /, boot, and swap.

All of the RAIDs are RAID -1



The first setup is the easiest for me to maintain as there is only one partition. But the second way i guess is how i should do it. The final system will have 512 MB Ram when finished so do i need to worry about a swap partition and just stick with a swap file, i have no idea about the boot.

What do you guys think? What set up shall i use? (i would like to use the first one )

Im using lilo as the boot loader as GRUB has problems with RAID 1 - is there any fixes yet?

Thanks Tim


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You where all a :newbie: once!

Come on guys, some help please

I'd probably go with the second setup, with separate partitions. I know a little about RAID, but haven't actually tried setting one up, but separate partitions are usually a good idea in any situation. Maybe it's different for RAID, though. Have you checked out the ATA RAID Howto? There are a bunch of other related RAID howtos at tldp.org.

Thank you for your reply. I had a look at that how to, but i still cant see anything that say's you must have three different partitions. If anyone else has a opinion please let me no!

Thanks again

re: partitions

making each part of the system - i.e /boot /usr /var /tmp / etc - live on a seperate partition makes fixing things (and restoring files from backups) easier.

Put /var on a seperate partition, that way if your logs pile up, they can only max the space on one partition, rather than the whole disk (s).

I assume the fileserver will only be accessed from the LAN?

re: RAID

depends...(crap answer, I know)

What are your aims for RAID? Backup purposes or speed of access?

If you want speed, I'd use disk striping. RAID 0. The data to be saved is broken into small portions and is written sequentially to all disks simultaneously in small areas called stripes. Because all the read/write heads are working constantly performance is increased. (and when reading data the same performance gain is noticed). You also get to use all your space for data.

If you just want stability / backup - stick with mirroring.

If you can afford / find another 2Gb disk use RAID 5 (stripes with parity), it's fast and provides decent backup against disk failure. Providing only one disk breaks, the data can be restored from the parity information on the other two disks.

Thank you for your reply. if i do do different partitions i will stick to 3 (boot, / and swap) i find it hard holding on to 3!. i will be using raid 1 as backup support (i no I no! its not my only backup don’t worry :) ) its not a crap answer, thank you for your help :D . Any other ideas anyone !!??

RAID 0 and RAID 5 does not improve accessing times. It improves data throughput. Instead sending and writing 20 megabytes per second with one drive. Two drives will read and write 40 megabytes per second. Both RAID 0 and RAID 5 should be used for video, graphics, sound, or be use a file storage for all the computers on a network.

I would go with partitioning the hard drive. Plan your partitions well so you don't have to resize. Use a journalizing filesytem like ext3 or ReiserFS.

You should not use your OS drive to be used to store files for your users. You should use another drive for this so that LINUX can do other work on its own drive while the other drive is serving people their files.

Keep in mind that 100 Mb ethernet can output ~10 megabytes per second, so RAID 0, RAID 5, or RAID 10 will not help much. One drive can easily output more than 10 megabytes per second.

Thank you for your reply. I do agree that the OS should be on a diffrent drive, but i wont the OS to be apart of the RAID mirror. How about if i make four partitions boot, /, swap and data?? also do i need to worry about a swap partition and have a file as i will be using 512MB ram on the file server? Thank you for your answers, if you could just help me a bit more :D