Comments on: The new CA server has arrived

By: Graham Smith

Graham Smith — Wed, 25 Mar 2009 03:30:26 +0000

well, at least this is one post on CA that is troll free!

By: Jeff Id

Jeff Id — Sun, 22 Mar 2009 15:45:32 +0000

Thanks Anthony, The efforts are VERY appreciated.

By: SMSgt Mac

SMSgt Mac — Sun, 22 Mar 2009 05:14:10 +0000

I design, direct, and signoff on the certification testing of some of the most advanced weapon system avionics and avionics laboratories on the planet.

And I say YOU SIR!, are such a geek

By: Stat Trader

Stat Trader — Sun, 22 Mar 2009 02:54:10 +0000

Fair enough, but please think about it next time. I’ve had many issues with RAID5 sets going bad, and they are slooooow.

By: Anthony Watts

Anthony Watts — Sat, 21 Mar 2009 20:27:28 +0000

I appreciate the input, but the system is already configured for RAID5, and I’m loathe to go back to ground zero now.

By: Paul Penrose

Paul Penrose — Sat, 21 Mar 2009 19:15:59 +0000

Re: Stat Trader (#48), I agree. RAID 1 on three disks will provide more reliability and better performance at the cost of usable disk space. Given the size of these drives I think that's a reasonable exchange. I can't see CA needing more than 500Gb over the next couple of years.

By: Stat Trader

Stat Trader — Sat, 21 Mar 2009 13:44:17 +0000

The reason I’m plugging on with this is because of the reliability issue. With RAID5 on three disks, if you loose two disks you’re dead in the water. With a three way mirror (RAID1 on three disks), if you loose two disks you’re still live. A three way mirror will also read 50% faster than two way with a hotspare and over 50% faster than RAID5. The *only* reason for choosing RAID5 is for economy when you have to store a lot of data — which you don’t — and you’ve already purchased the disks. Plus, most modern RAID controllers should be able to reconfigure from RAID1 to RAID5 while the volume is still live — so if you end up needing the storage you can get it.

By: Mark M

Mark M — Sat, 21 Mar 2009 11:22:09 +0000

Nice work Anthony! I probably should have suggested SliceHost rather than an EC2 instance. For your CoLo costs alone, a Slicehost “slice” would have given you the same capacity – hardware hassle free! Out of curiosity, how many dependencies does the CA WP instance require that you can’t rysnc the directories straight to your new server along with a mysqldump? BTW – I have hardware envy!
Regards.

By: John A

John A — Sat, 21 Mar 2009 11:07:36 +0000

Re: Stat Trader (#45), I think the emphasis is on resilience to hardware failure rather than actual read access speed. I'd agree with you regarding the actual disk capacity is overkill (and then some). Steve stores a lot of documents, scripts, presentations and data which are not in the database but are offered as resources to the scientific community. I expect this will continue and grow in the future. I just checked and the space taken by the Climate Audit www directory is 1.6GB

By: Stat Trader

Stat Trader — Sat, 21 Mar 2009 01:58:31 +0000

Re: hswiseman (#43), Sorry to be a stick in the mud but RAID 5 does not read faster than RAID 1. RAID 5, which to read all n member disks and then check the parity to serve one page, cannot read faster than RAID 1, which is able to read an independent page off each mirror member and serve them simultaneously. You can build a RAID 1 with any number of disks greater than 1 and for n disks the read speed is n times the write speed. The reason for RAID 5 is because it is more cost efficient; but it is less reliable and less fast than RAID 1 — but do you really need 500GB for a blog? I admin a SQL server database with a 300 GB store (storing financial tick data) and that is a HUGE database. There's a nice write up on wikipedia.