Hello David,
>True VK, MSFT has incorporated RAID-0, RAID-1, and RAID-5 in NT,
>while NOVL only bundles RAID levels 0 and 1. (cheap shot, but it
>just goes to show that MSFT can do some things right).
I have to say that your perspective on "right" is quite interesting. I assume that you have extensive experience with the NT version of "RAID-5" and know the reasons that it is there ... and also know the limitations?
NT *had* to include a software solution that would allow them to escape the limitations that they designed into the NT Operating System. Because Microsoft stuck with the FAT file system for so long they became crippled by the limitation that NT has no way to "span" physical disk partitions with a single logical drive. NTFS didn't fix this either!
What this means is that NT can not support a logical drive larger than one physical disk drive ... my network volumes sizes are limited by the hard disk manufacturer!
So the solution? Microsoft added a crude software RAID-5 which allows you to combine several physical drives into a single logical RAID-5 drive, which can then be used by the OS as a single drive. This allows them to escape the limitations of a poorly designed file system ...
Oh and let's look at the *real* benefits of RAID-5 ... hot swap and recovery! Ooops ... that's not supported by NT! If a drive fails, the server keeps running, but you have to shutdown and reboot to rebuild the RAID-5 configuration! That must be real impressive fault tolerance for *some* people ... but not the customers I deal with. ("Hey boss, that investment in fault-tolerance paid off ... the server didn't crash, but can we tell the whole company to logoff so that we can rebuild the failed drive?")
The other day I had a drive fail on an NT test server that had simple RAID-0 enabled (disk mirroring) and to re-mirror I had to reboot!
I have a NetWare test server that I am constantly hot-swapping, re-mirroring, adding and removing disks ... all while the server is running and available. I also have a 155GB disk subsystem that can be configured as a single volume if I want ... and I can also support all the *true* hardware RAID-5 subsystems out there ...
Yeah ... that checkbox on the marketing literature sure must look good ... but anyone who's job depends on keeping the network up knows what that superficial stuff is worth.
>I20 has also been blessed by HP, and their compliant products will
>be shipping shortly.
And as I have endorsed I2O on this list before I will continue to do so! I2O is fully supported by Novell, with numerous people on the various committees working on the standards ... I will predict that NetWare supports and can truely utilize I2O far before NT will ... including these new HP products ...
Scott C. Lemon |
