AV-Server: 1TB total disc-space, how would you set it up?

Master One · l33t Joined: 25 Aug 2003 Posts: 754 Location: Austria

I am just planning to set up a lan-server, which also will contain disc-space for holding a lot of video and audio files. It's an Athlon-XP 2500+ with 1 GB RAM, latest gentoo-dev-sources 2.6.5 and the following HD configuration:

2x 36 GB 10000 RPM U160-SCSI on an Adaptec 29160 as softraid-1 holding the system itself

2x 160 GB 7200 RPM SATA on onboard Sil3112A
2x 250 GB 7200 RPM ATA/133 on onboard Pri/Sec IDE Master
1x 250 GB 5400 RPM ATA/133 on IDE PCI controller (which I want to buy tomorrow)

The mentioned large HDs will only be used for video and audio files, as well as for backups from other computers on my lan.

I think I will set it up as one large striped logical volume on a LVM2 volume-group containing 2x160GB+3x250GB=1070GB with XFS as filesystem.

Any comments on this project?

Would anyone suggest EVMS2 instead of LVM2?

Could it cause a performance issue, that the last 250GB disk has not the same RPM (as well as the speed difference between the SATA and PATA drives)?

Would anyone go for linear mapping instead of striped mapping?

I am just curious, if anyone else has successfully managed such a system.
_________________
Las torturas mentales de la CIA

JPMRaptor · Guru Joined: 04 Oct 2002 Posts: 410 Location: Maryland

The reason for striping the drive is to increase the HD data transfer speeds. If you can get the performance you need out of a linear mapping then it comes down to which is easier for you.

Master One · l33t Joined: 25 Aug 2003 Posts: 754 Location: Austria

Yes, a little performance boost due to stiping would be nice, and there is no difficulty in setting it up using LVM2, so it does not matter if linear or striped mapping concerning the setup.

As I under, using LVM the way it is planned, has about the same effect as Raid-0, so if any of my harddrives fails, all data is lost anyway, so it also makes no difference concering data-security if linear or striped mapping. I do not see any chance for having 1TB secured in any way, and also no kind of backup for such a hugh amount of data comes to my mind.

Therefore I think the LVM2 striped mapping should be the way to go.
_________________
Las torturas mentales de la CIA

Starborn · Posted: Sun Apr 11, 2004 7:49 pm Post subject:

You say you're going to be backing up to this volume? These are all ide disks using the equivalent of raid zero (lvm striping) - in my experience this isn't going to last too long. Have you considered a soft raid 5 setup?
_________________
"I think ecchi things are bad" - Mahoro, Mahoromatic

"I think ecchi things are good, especially mahoromatic" - Me.

BradN · Posted: Thu Apr 22, 2004 5:14 am Post subject:

The place where raid kind of loses appeal is when the drives are different sizes, like in this case. maybe you could split the 250GB drives into two 125GB partitions each, and only use 125GB of the 160GB drives... so you would end up with a bunch of 125GB partitions you could raid-6 together, and since any drive doesn't hold more than two "units" of data, you can safely lose a drive and not lose data with it. I suppose you could raid the remaining free space (35GB) on the 160GB drives together and add those to LVM as well... this would get you 125*8+35 = 1035 'metric' gigabytes, and you can handle one drive failure without negative effects.

this gets to be an insanely screwed up setup though. You'd have to write down what each partition does so you would know how to restore it... Otherwise you could raid-1 the two 160's together, and raid-4 the 250's and end up with 160+2*250 = 910GB.

Master One · l33t Joined: 25 Aug 2003 Posts: 754 Location: Austria

I took some time, but now I have built this terrabyte monster, also I went another way in doing that, as planned at first.

I overthought the hardware, and I am now using other components:

P4 2.4GHz
1 GB RAM
Asus P4S533-X mobo
1x Adaptec 29160 U160-SCSI
2x ITE8212F UDMA133 (very cheap noname PCI card)
1x RTL8169S GigaBit NIC

with the actual development-sources 2.6.6-rc1 and this HD configuration:

2x 36 GB 10000 RPM U160-SCSI softraid-1 with reiserfs (ext3 for /boot) holding the system itself and /home (which is used for storing smaller files, like documents)

6x 250 GB 7200 RPM PATA/133 softraid-5 with reiserfs holding /share

The setup was easy, all components found their way into a midi tower with 5 HDDs mounted in 5.25" drive-bays, 3 HDDs in 3.5" drive-bays. Due to missing space, I removed the CDROM drive after the installation. The 3 HDDs in the 3.5" drive-bays get very hot (and I mean very very hot), you can not put your finger on it for more than 3 sec. But I do not care, I read the drive specs, and there is no limitation on the drive use (MAXTOR MaXLine Plus II, granted for use without fan, needs only about 1 mm above and below drive, this is a not so expensive high quality drive for server use). Each IDE drive has its own IDE channel.

This storage monster gives me a total of 1.25 TB. Using the 6 IDE drives as a softraid-5 was the very best solution, as I think it is nevertheless better to have some redundency when using so much drives, if one goes, no data is lost. I would not suggest using LVM / EVMS or a simple softraid-0 for such a setup any more, also when using it for data with no need for security. I went for reiserfs instead of the previously planned XFS, because mkfs.xfs didn't want to format my md-device (a known bug, latest unstable version would have worked), and as I have read on the forum, XFS does not perform well on a softraid-5.

What I am very surprised of, is the fact that my softraid-5 is pretty fast! I have seen a lot of comments, that a softraid-5 is performing very poorly.

Take a look at my hdparm results. The values are a good deal higher when the system is idle, but it is actually under heavy load as I am just filling my raid with large AV-data over the LAN at the moment. The first results are for my U160-SCSI softraid-1:

Ian · Posted: Sat May 08, 2004 4:14 pm Post subject:

How much did all of this cost, might I ask?

Master One · l33t Joined: 25 Aug 2003 Posts: 754 Location: Austria

I am sorry, I can't really tell, because most parts I used, are not really bought new and were just laying arround here...

When building such a machine from scratch, it can be done cheaper and simpler, than I did. The most expansive parts are the 250 GB HDDs, which go for about 180,- to 200,- EURO each. For a low budget terrabyte server, I'd go with the used softraid-5 solution, especially as such noname IT8212 add-on cards can be bought very cheap. On the other hand, if I would have to buy all parts new for such a project, I probably would go for a hardware raid controller, there should be some not that expensive.
_________________
Las torturas mentales de la CIA

BradN · Posted: Wed May 26, 2004 10:57 pm Post subject:

i'd avoid running drives that hot if at all possible....

Master One · l33t Joined: 25 Aug 2003 Posts: 754 Location: Austria

I know, I also would like to have them a little cooler, but I see no way in installing any more fans in that miditower, which is pretty full due to the 8 drives altogether. The temperature in the inside is not that bad, and the case itself is not warm at all, it's just the drives, but I assume these Maxtor drives get usually pretty hot, so they surely are designed to operate at that temperature. Anyway, I don't really think that higher temperatures are bad for harddrives, and I do not think that this will shorten their lifetime.
_________________
Las torturas mentales de la CIA