Raid 1 / Raid 5

[Pete Suttner]

Hi, I'm considering external storage options in the 4 terabyte range. Firewire 800 for archiving scans. What are your thoughts on Raid level?

[Ron Marshall]

Depends what you are trying to achieve: greater speed or redundancy?

http://en.wikipedia.org/wiki/RAID#Standard_levels

[Pete Suttner]

Redundancy.

[Ron Marshall]

RAID 1 then.

[SergeyT]

Make backups and keep them away. Cheaper and more safe.

[Darren Kruger]

Hi, I'm considering external storage options in the 4 terabyte range. Firewire 800 for archiving scans. What are your thoughts on Raid level?

With RAID 1, you only get to use 50% of the raw space of the drives. But it is very easy to get back going if a drive fails. RAID 1 by itself doesn't combine the space across drives. For that look for RAID 1+0 (sometimes listed as RAID 10).

With RAID 5, you get better space utilization as you only lose one drive's worth of space over the full array. If you have four drives you would have free space equivalent to three. Reads and writes are across multiple drives for a possible performance boost. Cards that support RAID 5 are more expensive.

RAID 1 requires at least 2 drives. RAID 1+0 requires at least 4 and RAID 5 requires at least 3 drives.

are you sure you need RAID support for external storage for archiving scans? There is something to be said to having multiple copies of the same data on different disks and then storing one of those copies offsite.

-Darren

[JHenry]

Pete.

Take a look at Drobo (www.drobo.com). This is what I use. Initial cost is a bit higher since you have to buy the device. But, for ease of use and redundancy, I find it to be great. Also, it is perfect for the non-techie who just wants the ability to do easy and automatic backups, with the ability to scale up if/when needed.

Of course, this keeps a complete backup of everything onsite. For absolute true backup, I'd occasionally make a back up of all my files onto an external hard drive and keep it offsite.

Cheers,

Jeff

[Richard Mahoney]

Hi, I'm considering external storage options in the 4 terabyte range. Firewire 800 for archiving scans. What are your thoughts on Raid level?

RAID 1 with hot swap drives and automatic failover to pre-assigned standbys: dead drives can be pulled and replaced at *your* convenience not when the inevitable failure occurs. Get the best drives you can afford, always cheaper in the long run. I'm still using a set of 4-5 year old 15K Ultra-320 SCSI disks and they haven't had an easy life. They should be nearing end of life for server disks. I'll probably be replacing with SAS drives when they finally cark it. Redundant disks are only part of the story. Off site storage is a must. For a relatively cheap and simple solution Amazon S3 should be your friend.


Kind regards,

Richard

[Darin Boville]

Redundancy.

Then you have to ask "why"?

If you are trying to insure against fire or theft--or lightning hitting the house--then all that RAID business is just more consumerism. The geek's version of the Viking oven.

I use Time Machine + periodic back ups that are kept in my car. I keep taking about copying my photos, (especially the good ones!) and sending them out of state--I really should do that given that I live on a fault network...

--Darin

[mhanc]

Belt and suspenders:

1. Time Machine back up 2nd drive. Good for file recovery - can be used for disaster recovery.

2. CCC (Carbon Copy Cloner) for periodic complete disk backups to 3rd drive. Good for disaster recovery.