I have researched this and changed my ideas over and over again. I turn to everyone for what guidance and experience they can offer.

For some time now I have been meaning to use my old computer hardware to setup up a machine as separate NAS for my home. The purpose of which would be sheerily for storage, and not performance (streaming media etc.)

For this exercise I am more than willing to take the performance hit and embrace a ‘software’ RAID 5 setup – due to cost of ‘hardware’ alternative with onboard XOR processing.

For such an exercise I was originally going to use the Windows XP hack for RAID 5 on my main machine. However, I am in a quest for greater functionality.

Particularly I am looking at the alternatives of Windows Server 2003 and in particular, Linux (of which I have no experience, but am very interested to develop my knowledge) on a separate box.

With recent advancements I am keen to deploy this functionality:

• Expandability – That the array size can be grown with the addition of extra drives (A particular of the recent Linux kernel as I understand). Also whether it forms space as part of the main pool.

• Better to partition the RAID 5 array with separate drives for each media type (music, tv series etc) or use as a single pool of space.

• I have seen somewhere (very vague) the option of different sized HDDs and using the normal loss in space for the extra drive (parity) as a separate partition (not as important… just for future proofing upgrades).

• To have the array be functioning/accessible across Windows machines in a home network.

• SAMBA, FTP, accessibility away from the network and other interesting options available.

• E-SATA: Peoples experience with expanding for more drives via this option.


Can everybody share their personal experiences with such a task. Links? Recommended builds of Linux etc?

This is in an effort to compile recent advancements and knowledge for such a task that I wish to share as a resource. Also to see other peoples ideas.

The specifications of the machine will be as follows:

AMD64 3000+
1Gb DDR400
4x400gb Seagate SATAII drives
1xHDD for operating system etc.

(Parts spare from recent builds etc).

My apologies for the detail, but I seem to be going around in circles and would like some clarity.

-Alex

Linux will do the job great for this. There are many RAID5 appliances built like this on Linux, like the Buffalo Terastation or the Systemax Mini-Vault. You can get on of these, which come with 1TB of storage for about $1000. This is what I would recommend for you; it's cheaper than the PC you wanna build and it uses low consumption of electricity and it'll save you on electric bills.

If you still wanna build one yourself from scratch then that's also good. You can grow the array as you add more drives using mdadm and lvm. In general RAID5 starts to have problems after 14 drives so you should be fine with 3 drives to begin with and the option to add a few more.

RAID5 will use one third of your total space for redunandcy. So if you have three 400GB drives you will get one partition of 800GB. But if one drive fails you'll still be up and running. If two drives fail you are dead in the water. Make sure you perform backups.

The rest you can do SMB, FTP, etc...

That is true. Here is a good link explaining briefly how it is done - http://scotgate.org/?p=107 The resizing of the space will be accomplished by the steps listed in that link. It will increase the size of the array, which in turn increases the size of whatever you have it mounted as.

I would make one big pool. Say you do split it into different pools, all mini-raid5 setups, then you get several large dvd movies, and another of the partitions fails. You might not have the space to spare to copy things around. I think it would be far better to have only a single large pool of space, and break it up as you see fit.

[quote[• I have seen somewhere (very vague) the option of different sized HDDs and using the normal loss in space for the extra drive (parity) as a separate partition (not as important… just for future proofing upgrades).[/quote]

That sounds like garbage. I think what you're getting at is leftover space, and what to do with it? Say you have 2 120 Gb drives, and the 3rd is 200. To make a RAID 5, you'd partition off a chunk of 120 Gb from the 200, combine it with the other 2 120 Gb drives, and have a 240 Gb RAID 5 partition, and 80 Gb of extra space. You could combine all the left overs into a JBOD style array, but you'll have no redundancy that way. I wouldn't mess with the extra space.

That will be easily accomplished by the samba server program.

Samba for within your network, ftp from outside should be fine, assuming you configure the pass through correctly on your router.

As near as I can tell, this simply means storing your SATAs in an external location from the case of your computer.

Any build of linux will be fine for this. I would try and get friendly with a few different live CDs, and see what feels the best to you. Many people like to start with a training wheels style linux, like Fedora or Suse, and to a lesser degree Ubuntu. Those are a fine place to start, and then from there see what you like and dig deeper to see what fits you the best.

This is true, although anyone running RAID 5 with that many disks needs their head examined by a mental health professional. RAID 6 is the way to go for the most space + failure tolerance. RAID 6 can tolerate 2 drive failures, RAID 5 only 1. Also, no mobo is going to handle more than 4 sata drives, so it makes little difference to the OP. If you want more than 4, you'd need a card for them, in which case you step up to hardware RAID, and live the good life.

This is only true if you make a RAID 5 array out of only 3 disks, which is the minimum needed for RAID 5. The formula for RAID 5 is (n-1) * size of disks. So with 4 400 Gb drives as the OP states, he'd get (4-1) * 400 = 3 * 400 = 1200 Gb of space. He lost one quarter of the space, and if he had room for one more disk, he's lose only one fifth.

Peace,
JimBass