[svlug] Help connecting 60 Gig Raid Array

[Alvin Oga]

hiya ben..

> The storage space will be used for tools, all of those CDs one gets from
> companies like Cadence or Synopsys, so in case of catastrophy, we could
> simply re-install. Backups will be done to a DLT4700 tape jukebox - each
> tape holds 20MB (40 compressed), so 2 or 3 partitions should be about right, 
> and most of the time the array will be mounted read-only.

backing up 60Gb to 20 tapes is NOT easy....

I'd NOT backup synopsys, cadence etc since it's vendor software that you
installed from CD...

I'd make sure no one write "user data" to that drive...

than a simple find "new files" will suffice for incremental backups 
using the cdrom as the "full backup source to patch incrementally"

> One advantage of the IFT-3102U controller is that it is managed via RS232, so
> it is OS indipendent. It can divide the physical array into logical units,
> each of which can be Raid 0, 1, 3, 5, or JBOD (just a bunch of drives).

this is true of the h/w raid systems i meesed with...has rs232 port...
	( cmd, syred, ?? )

> So - more questions:
> One of you suggested that partitions be no larger than the backup device.

no reason why not...since the "backup" is the installation cdrom...
and  can do incremental backups from the date of the installs..

> OK, should I treat the array as one huge logical unit, and partition it
> the way we normally do, or should I break the array into multiple LUNs
> (which would allow me more partitions, but the multiple LUNs will confuse
> me, if not Linux).

we used channel-a and channel-b on cmd and syred and it confused the
system really bad....
	raid# cp 1Gb_binary.file  another_test.file
	raid# sync
	raid# diff 1Gb_binary.file another_test.file -->>FAILS<<--

> We currently have Slackware, RedHat, and SuSE systems here - any comments?)
 
I use rh-5.x and the raid box is treated as a regular scsi device...
all the "raiding" is done internally to the raid box...

> About the IFT controller - anyone have any experience with them? What are
> the alternatives if this works well enough that management wants to do it
> again?  Alvin mentioned the BT958 - we want to support the Buslogic folks
> (whatever they are called today), how does one manage the BT958? A card
> seems less versatile than a stand alone array, too.

since the raid box we have are just like a simple scsi device...
a simple scsi or differential scsi controller works fine (flawlessly) for us...
( it is used as /home for all the users...so if something went wrong... 
( guess I'd hear about lost files etc...
	- and yes...I took out the adaptec 2940uw that used to drive it...
	- too many scsi timeouts and stalled "edits"..than bursts...

> > - If your partition gets hosed you lose 60G of data
> > - If you have to fsck, you can go for lunch and come back.

yup...takes me about 45 minutes on a P200 for that size raid box

Personally... I think it's better to have two "mirrored" mirrored
and stipped  linux systems than to have a expensive hardware raid ( $20K ? ) 
	- you have built-in backups
	- you have "hardware balancing" for the computational cpus
	- you have more headaches if not careful !!! :-)

have fun
alvin

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