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Digital Personal Workstation 500au becomes a server - Alex Belits
Digital Personal Workstation 500au becomes a server
Some time ago nickhalfasleep gave me an old Alpha workstation that was too slow for its original purpose, and didn't have enough storage to be useful as a server. Separately I had a box of old 36.4G Compaq drives with SCA connectors, and SCA to 68-pin SCSI adapters. So in theory I could add a RAID array, and end up with a usable server.

The problem was, putting those things together was not a trivial task. Digital Workstation has plenty of space inside, however there are only three positions for drives in front and two in the back. With all five positions filled with drives, it gives me 182G total with no redundancy. Worse yet, power and cooling in the Alpha case, while being more than sufficient for its original configuration, are not likely to be usable for any additional hardware. I didn't want to add an external SCSI enclosure for a seven years old box, so I have decided to slightly modify its case to fit seven drives and an additional power supply for them. Yes, that would be a Digital Workstation case mod, something that, I believe, not even 1337'est of 1337'est case modders would consider doing ;-)

First of all, I needed to put in the drives. Two drives in the back are already close enough to each other, so the only available space was in front. I have made a cage that holds five drives vertically, and a 120mm fan in front of them, so cooling remained sufficient even though it was five SCSI drives in a space where at most two hard drives, floppy and a CD drive were supposed to be installed.

I have connected five adapters' power wires in parallel, ground of the first power supply with the second one, and PS-ON to the ground, so five hard drives turn on immediately when the second power supply's AC cord is plugged in. Two more SCA adapters sat on the hard drives in the back, connected to the first power supply without modifications.

Then I had to make a bracket for the second power supply. There was enough space at the bottom near the motherboard, right in front of the PCI cards, the airflow in that area wouldn't change much because of the power supply, and slight increase of the air temperature would have no noticeable effect on the rest of the box. Floor of the case has some conveniently placed loops, so the bracket just had to have two small protrusions to fit into those loops, and the rest can be easily held by the outer wall of the case.

I have installed a USB2 card for an external backup drive, added 60mm exhaust fan in the back,

And this is how it's configured:
abelits@dvk3:~$ uname -a
Linux dvk3 #2 Mon Aug 1 17:38:21 MDT 2005 alpha GNU/Linux
abelits@dvk3:~$ df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda2              1451376    433204    944444  32% /
tmpfs                   256680         0    256680   0% /dev/shm
/dev/sda1                57509     13801     40739  26% /boot
/dev/sda6             10321208    411396   9385524   5% /home
/dev/sda4              1358612     32836   1256760   3% /tmp
/dev/sda3             10321208   3175900   6621020  33% /usr
/dev/sda5             10321208    401728   9395192   5% /var
/dev/md0p1           175038720 119906256  46240996  73% /volume1
tmpfs                    10240      5512      4728  54% /dev
/dev/sdh1            240362184 125450660 102701748  55% /media/backup
abelits@dvk3:~$ cat /proc/mdstat
Personalities : [raid5]
md_d0 : active raid5 sdb[0] sdg[5] sdf[4] sde[3] sdd[2] sdc[1]
      177829440 blocks level 5, 64k chunk, algorithm 2 [6/6] [UUUUUU]

unused devices: <none>

I realize that after all those changes it's still far behind anything modern, especially compared to things that we build now. Nevertheless it runs NFS server, and handles backups for all other boxes at my work, what makes it useful.

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2 comments or Leave a comment
mackys From: mackys Date: November 9th, 2005 12:50 am (UTC) (Link)

Very nice!

Well done. Damn.
From: nickhalfasleep Date: May 4th, 2006 05:54 pm (UTC) (Link)
Nice job. That case is very unusual and I think you made the best of it.
2 comments or Leave a comment