I'm using a variety of DPT raid controllers, namely the 2144 and the 3334.
I prefer the latter, as its much faster.
They use a dos-based tool to configure the RAID, but once its built, linux
sees the device as a standard scsi (sdX) device, which you do not need to
use the linux raid tools or raid support. The RAID device is completely
transparent to Linux. Hot-swapping is only available if you use DPT
enclosures; otherwise you have to pull the disk, shut down, put in a new
disk and then rebuild. Rebuilding is automatic and backgrounds, so the
system is operational (in degraded mode) while the disk rebuilds.
I've already survived 2 disk failures in our arrays without loss of data.
Incidentally, linux softraid support has really matured. I'm using 2.0.35
+ raidtools 0.90 on 4 production servers and I must say that the product
is incredible. I've also survived a disk failure on a system with no loss
of data or downtime (other than the time it took to replace the disk). Its
good stuff, the raid syncing takes place in the background like the DPTs
do. Linux 2.0.30's raid145 patch and raidtools require you to ckraid
before the filesystem is usable, instead of a background raid check. So on
some of our systems using the old raidtools, it takes 4 hours to ckraid
and e2fsck, with the new raidtools, the system reboots as normal (a few
minutes).
Anyways, I do recommend the DPT RAID controllers if you are really
concerned with the integrity of your data (RAID5). If you're into just big
arrays, performance and some reliability (like raid0 for a news spool),
use linux softraid, it can be faster and it works pretty well (not to
mention its cheaper ;)
- liem
On Mon, 30 Nov 1998, Glaza, Lorenz wrote:
> Date: Mon, 30 Nov 1998 13:20:56 -0800
> From: "Glaza, Lorenz" <[EMAIL PROTECTED]>
> To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>
> Subject: DPT Raid Support
>
> Has anyone tried a DPT RAID card? Specifically, I am looking at the
> following model:
> PM2144UWR
> PCI-to-Ultra/Wide High-Performance SCSI RAID Controller
> High-performance, single-channel PCI-to-Ultra/Wide SCSI RAID controller.
> Includes PM2144UW Ultra/Wide SCSI Adapter <pm2144uw.htm> (more powerful
> processor, faster internal DMA paths) and RC4040 RAID/Caching Module.
> <raid-cac.htm> Supports hardware RAID 0, 1, 5, 0+1 and 0+5 with room for
> up to 64MB of standard or DPT ECC Cache SIMMs (0MB included).
> Much Appreciated,
>
> Lorenz Glaza
> Transamerica Life Companies
> Special Studies/ALM
> 213-742-5049
> [EMAIL PROTECTED]
> http://lo-lands.ml.org
>
============================================================================
Liem Bahneman [EMAIL PROTECTED]
Senior Systems Administrator http://www.cobaltgroup.com/~roland
The Cobalt Group (206) 269-6363 x300
Seattle, Washington F(206) 269-6350
