SSD Caching Server

The next issue I have been facing is that while I CAN netboot 16 pi’s off one NFS server (That’s not a problem at all), it is when my ‘large’ available storage is my iscsi SAN.  I tried having a VM which mounted an iSCSI target and then NFS-shared it, but that’s just not working fast enough.  Time to investigate SSD caching.. the Kernel DMCache driver looks pretty good..

I have this old Lacie ‘Gigabit Disk’ NAS – it’s has an 800MHz VIA CPU with 4 x 250GB IDE drives in it.  It became too slow years ago, but I’ve recently picked up some H61M-ITX mini-ITX boards which work were selling off.  Think it’ll make a nice upgrade for the NAS 🙂


It’s a nice little unit.  Think it’ll fit what I want to put in it pretty well.IMG_3580IMG_3589

Sweet, that fits!  H61M-ITX, 16GB ram, and an i7-2600.  And 8 x 240GB M500 SSD’s for the caching.  They’ll run on the 3ware 9650se-8lmpl raid card.


Network Cabling

Power is back on, and we’re over most of the damage, so time to get back into the PiCloud!  It’s time to sort out network cabling.  This took some doing, as I had to dismantle the chassis at the rear.  But now it’s sorted 🙂


Power Out!

Ugh!  We just had an EPIC storm, and currently have no power other than what I have in all the deep cycle batteries in all the UPS’s etc.  But I’ve been a bit lax since we shifted into this house.  Settling into becoming a Family man and all that.  Used to be I had a go bag, plenty of spare fuel, auto-start genny. The works.  This has caught me out fairly hardcore.  Mobile network is down, as EVERYONE is trying to use it as noone has a hard-line phone anymore – they’re all DECT handsets whose base stations don’t work when there’s no power.  Plus I give it 24hr and we’ll have NO mobile network anyway..

So we need power to the comms gear.  When my old work moved out of their old office into a new one, I scored a bunch of DC UPS’s.  Little APC 40V jobbies with 24v daughter cards.  The Mikrotik router will take 24v happily, but the TPLink DSL modem? Not so much. It wants 5v.

IMG_3150IMG_3152 Yep, that works nicely 🙂


Yeah! Internal work done!

So today I put four circuit breakers in – three for the three rails to Pi’s, and one for the rail supplying the Arduino, relay driver board, and the Relays themselves.


And then it was time to properly mount the Arduino, and make sure the relay driver was insulated ok 😉 (Yes, I used cardboard :-p )


It looks pretty darned sweet though!

IMG_3111P4060773 P4060774P4060775

Now it’s time to put the Pi’s on their Perspex carrier boards.IMG_3112IMG_3115

And the moment of awesomeness.   SIXTEEN Pi’s MOUNTED AND INSTALLED!IMG_3116 IMG_3117 IMG_3118

Yep, that is beautiful!   Hmm, need to sort out network cabling now I guess..

Cabling almost done!

Yep, I was right. That’s a LOT of ribbon cable!  It should sit fairly cleanly though 🙂


It’s also a LOT of normal hookup wire.


Finally fitting it all into the chassis.  It actually fits VERY nicely!IMG_3096IMG_3099

Yes, I plait my cables.  Always have (You should see my rack cabling :-p), always will 🙂IMG_3100IMG_3101

Module 1 wired!  And time for Module 2


Oh, you know how I said the wire on the ATX extender didn’t look thick enough? Yeah, it wasn’t!  Melted the first time I fired it up!  Had to pull all wires from the socket, and run new cable from each pin.  That was the load of JUST the relays. (So ~2 A)