RAID10 over 6 devices

I’ve been struggling to find the best layout for my 6 drive RAID10 device: I settled for near with 2 copies, and a 1M chunksize. As far as I understand this I get the r/w speed equivalent to RAID0 with this. It means that each block has two copies, which are striped across 2 drives. So you get the RAID0 speed, with the redundancy of RAID1. Plus since this is kernel RAID10, it’s a lot easier to create and more flexible than a mirror of raid0 devices.
mdadm --create /dev/md1 --chunk=1024 --level=raid10 --layout=f2 --raid-devices=6 /dev/sd[defghi]1

So far the speed seems to be OK. Nothing at all spectacular though. At the moment I think my limitation is that I am running a 64bit PCI-X u320 card in a 32bit PCI slot since my motherboard only has these…. I need to get myself a PCI-X dual socket 604 motherboard. Trouble is these are quite expensive…..! In my quest to silence the machine I replaced the fan in my Graphics card with a quieter one. Unfortunately whilst doing so I knocked of a small component. The card works fine except that I get visual aretefacts on any hw accelerated graphics now. I’ve alwasy steered away from upgrading my motherboard due to the fact I would need to also buy a new GPU to go with PCI-E slots. But if this is now damaged perhaps I should splurge out. Hmmm.

Categories
Computergeekery trivial shennanigans

Scythe Kama Bay Black

Ok, so to solve the cooling problems, I’ve ordered 3 of these. I have 9*5.25 drive bays in the array box. So these should fit. They better be silent though….! It also begrudges me to order from a company who’d website does not render correctly on Firefox on linux. Works fine on OSX though.

Vadim Computers : HD Cooling – Scythe Kama Bay Black

Categories
trivial shennanigans

Backup using tar over SSH

I’ve now got a fairly large (0.5Tb) external drive. A Lacie. Now it’s a RAID 0 pair of 250Gb drives, which is not exactly a reliable backup medium. But I like it and since it’s firewire 800, it’s pretty dammed fast. Anyway, I normally backup to tape, which is good although slow. I just tried backing my Linux Home directory (~150Gb) to the external drive via SSH to my macbook. Where the drive is plugged in. Nice, fast and pretty cool.

tar -czvf - /home/ | ssh ferg@morcheeba "cat >> /Volumes/Backup/Homebackup16Mar07.tar"

Cool. eh!

Categories
trivial shennanigans

flash based SCSI drive

One of these babies would be a nice fit in my Christmas stocking. It would be an excellent move in my desire to quieten my 9 drive array since I started working from home.  It’s just too noisy. Currently plans are to migrate all the drives to a new SCSI case I just got. This will eventually go into the attic, attached using Gigabit Ethernet via iSCSI. I was planning on keeping a pair of drives for the root filesystem and boot. But I could net boot the system, and have one of these to act as the root filesystem. Onces booted the machine could populate the drive from an image on the iSCSI device.  Daft really, I doubt I could afford one of these, and there are certainly cheaper and better ways to silence the machine.

Anyway here’s my planned migration

  1. Move all drives except 2 18 gig drives forming the boot RAID1 array into a 9 drive SCSI case
    1. This is underway, except I’m having cooling problems.  I’ve been mounting the drives with some silicon rubber 3.5 to 5.25 converters. This really quietens the rumble, but had the added benefit of NOT conducting heat away! Damm!!
  2. build a simple system to act as the iSCSI controller.
  3. Move the entire case into the attic. Obviously after putting Gigabit Ethernet into the attic…..!!

I have good hopes for a quiet and still blisteringly fast system.

Categories
Comics trivial shennanigans

2000AD: 30 years of the future

BBC NEWS | Magazine | 30 years of the future

Thanks to Raj For reminding me that 2000 is now 30 years old. The main thing is that it reminds me how old I am. I remember seeing the advert for a new comic called 2000AD in a comic called Crunch (No wiki, no trace on Google. Did I imagine that?). However,it also reminds me of just how many very pleasurable hours I have spent reading it. Chopper wining Skysurf (the 2nd Chopper story), Wulf dying… Halo Jones killing Toby. Superb moments.

I still get the comic sporadically. It’s still good, but not as good as I remember it. have my tastes matured, or is the comic less original? Perhaps I just miss the big boots of Dredd, and the people falling into the Flesh Dozers! Ahh!

Categories
Computergeekery Tips trivial shennanigans

HOWTO Find broken symbolic links – Gentoo Linux Wiki

HOWTO Find broken links – Gentoo Linux Wiki

I was trying to find some broken links. however, although using
find . -type l

shows all links, it does nto use the cool flashing RED that BASH can do to shwo a broken links. So doing a quick Google turned me to this Gentoo howto: Nice n easy!
find . -type l | (while read FN ; do test -e "$FN" || ls -ld "$FN"; done)

Categories
Mac trivial shennanigans

HASH key on a Mac Keyboard with Linux

Right I’ve had a bit of a palaver with the HASH key on my Mac. Well actually with a Mac keyboard attached to a Linux box. After getting my nice new MacBook Pro, I had a issue trying to find the hash key. (How long until my nice new MacBook Pro loses the nice new?). Anyway to cut a long story short it’s ALT + 3. Not too much hassle, and apparently a common thing with Mac UK keyboards.

When i finally settled down to working, I’ve started plugging in the MacBook to my Del 24″ widescreen monitor, and sharing the keyboard and mouse via a cheap USB switch. So with two clicks I can switch between the mac and My Linux box, without the vast expense of a DVI/USB KVM (do they even exist?). The Dell has a VGA and DVI input. so that’s very convenient. To make it easier I’ve plugged in a Apple keyboard to the switch. Linux behaves quite well with this. However, for the life of me I’ve not been able to fathom out how to type HASH in linux with the Apple keybaord attached. Untuil now….

It’s CTRL + SHIFT + 3

How odd!

Categories
trivial shennanigans

WordPress 2.1.1 dangerous, Upgrade to 2.1.2

WordPress › Blog » WordPress 2.1.1 dangerous, Upgrade to 2.1.2

Eeek. Anybody who upgraded to WP 2.1.1 (released a few days ago), better upgrade to 2.1.2 pretty damm quick!