Raid Options

michael · #1 (**permalink**) 08-03-2006, 01:39 AM

RAID is a subject that I have never really taken the time to explore. I wonder if anyone would be kind enough to explain the differences between the different configurations?

Host Master · #2 (**permalink**) 08-03-2006, 11:04 AM

RAID

Hosts really need to have RAID 1 minimum on SCSI drives.

jeff1 · #3 (**permalink**) 08-03-2006, 11:16 AM

RAID5 minimum

michael · #4 (**permalink**) 08-03-2006, 07:23 PM

Thank you for the link, it gives a nice brief to the point of the various options.

StreamLine · #5 (**permalink**) 21-03-2006, 11:13 PM

Am I wrong or is RAID more susceptible to HD failure? Isn't it a few hard disks acting as one, sharing data between the two? If one fails, are you left with half of the info you need on one and the other half broken? Am I wrong?

TWD_Tony · #6 (**permalink**) 21-03-2006, 11:47 PM

Quote:

Originally Posted by jeff1

RAID5 minimum

Most hosts would love to offer Raid5 as standard, but most people are not willing to pay for it - Raid5 needs a minimum of 3 HD's.
With people wanting to pay peanuts for hosting and "budget" hosts poping up all over the place it would prove very difficult to sell hosting to joe puplic on the strength of Raid5

Raid1 is a more cost effective solution and should be considered a minimum for web hosting companies (IMHO)

monaghan · #7 (**permalink**) 21-03-2006, 11:48 PM

Quote:

Originally Posted by StreamLine

Am I wrong or is RAID more susceptible to HD failure? Isn't it a few hard disks acting as one, sharing data between the two? If one fails, are you left with half of the info you need on one and the other half broken? Am I wrong?

RAID 1 / RAID 5 / RAID 10 offer you protection against disk failure, this is the main purpose of the system.

RAID 1 is basically a mirror, each write to disk 0 is mirrored to disk 1 by the controller (you can do it in software, but I'd rather not risk it)

RAID 5 stripes the data over multiple disks using a "spare" disk, in the event that a disk is lost, then there's sufficient redundancy in the remaining set to continue. A hardware controller will also offer things like host spares and automatic rebuild of a new disk.

With a good RAID system, then you can pull out a disk and watch the controller spin up the spare disk and rebuild the system onto the spare disk all in real time with no user intervention. If properly setup, it can also raise an SNMP trap which could be intercepted by a monitoring system to generate a helpdesk call to get the faulty drive replaced, all in real time

Also, most smaller hosts won't have RAID as customers won't pay the premium for their account. If you're hosting mission critical or high transactional value sites, then I'd seriously consider choosing a host with a RAID bsed file system.