upgrading my RAID 1 Array

[Virtuo]

I have a RAID 1 SCSI array on an old DELL server that is running low on space and needs either a complete rebuild (which I cant be bothered to do) or a few new disks installed. I generally use Acronis for something like this (take an image, insert 2 new SCSI drives and build a new array and then copy the image to the new array) but does anyone else have any other bright ideas or fancy new software that I am unaware of?

 

[pdu]

Does your raid controller support online raid migration? If so, you can add new disks and then join them into the existing array, then either create new partitions on the empty space or resize your existing one(s) to make use of it. I'd still take a backup before trying though, raid is never a substitute for backups after all, it merely offers business continuitity in the event of a physical disk failure

 

[alanbold]

You should take a look at drobo products

Data Robotics, Inc.

 

[Former Member 1]

You should take a look at drobo products

Data Robotics, Inc.

Must admit that was my first thought... I was rather hoping some of the more technically au fait on the forum would dispell my perceptions that RAID1 was one of those things we left behind some time ago...

Surely a RAID1 system isn't really all that suited to archival work? We used them years ago primarily to gain speed... But we'd never use them for backup.

If budget allows is it maybe worth evaluating whether this system is approaching the end of its service life? Or is it already in a semi redundant role?

Luddite and cynic though I am DROBOs seem to be getting a good reputation for stability and simplicity; at least among A/V people... But perhaps in any case avoiding that rebuild is just delaying the inevitable?

Is the data critical at all? That would be my main concern...

 

[Lanarkshire IT Services]

Hi All

You won't ever gain much speed increase via RAID 1

If anything performance is decreased due to the double HDD writing work involved.

RAID 1 is a disk mirroring technology, ie data is written to 2 drives and if one fails, the other is "supposed" to take over in a failover sense.

And your only ever going to get the total space of ONE drive

As you are running out of space I would think that cloning and then applying to bigger disks is as good a solution as any.

Alternatively, if your server / RAID card etc allows you could add another another RAID 1 based on bigger disks and clone the first RAID to the 2nd. Maybe using the replaced drives as additional storage.

But you are really only doing what you mentioned originally

You have to ask yourself - "What am I trying to achieve via Raid?"

Performance, failover, HDD space?

Then go for a solution based on this

Regards

 

[Former Member 1]

You won't ever gain much speed increase via RAID 1

You do over the old IDE standard! :laugh: Back about a decade ago this was how we obtained the necessary speed to stream MJPEG video from a capture card...

 

[Lanarkshire IT Services]

You do over the old IDE standard! :laugh: Back about a decade ago this was how we obtained the necessary speed to stream MJPEG video from a capture card...

Hi There

I would have thought RAID 0 would have been better for that regardless of interface: IDE / SATA / SCSI

Could be wrong

Regards

 

[Former Member 1]

I would have thought RAID 0 would have been better for that regardless of interface: IDE / SATA / SCSI

Could be wrong

I honestly can't remember why we were using RAID1 rather than 0 ...It's so long ago! Possibly even more than a decade in fact. We built our first hybrid (linear-nonlinear) edit system in about '95 running Premiere 4.0; had about ten minutes of storage on it!

UDMA-33 obviated the SCSI set up for us... That has to be at least a decade ago...

 

[Virtuo]

Hi guys, thanks for your replys

I'll either just plod on and do what I was going to do (build a new array using my aging version of Acronis) or get an HP ML110/5 with a single 250gb SATA drive and chuck the image on that. The server is old, there is no budget really to replace it and I could probably get a RAID 1 HP 110 for the price of 2 new SCSI drives these days.

I dont think the card supports online RAID migration and I dont think there is any space in the box for a 3rd disk, I also only want one partition. I am happy to use Acronis, just thought someone might be using some other software that they liked (just being a little lazy).

Drobo - The server is currently running SBS2003 so although the Drobo products look great for external storage, I really need a server.

Technically RAID 1 should always be slower than no RAID or RAID 0. under RAID 1, twice the info is travelling around the bus and as Lanarkshire IT said, all RAID 1 is really doing is creating a "redundant" drive based on the primary (ropey sectors and all). RAID 0 should in theory be faster at reading than no RAID and will be faster than RAID 1. It may have been the move from IDE to SCSI (5400rpm to 7200rpm back in the old days) that increased the read speed of mpeg rather than RAID.

thanks again.

 

[Former Member 1]

Technically RAID 1 should always be slower than no RAID or RAID 0. under RAID 1, twice the info is travelling around the bus and as Lanarkshire IT said, all RAID 1 is really doing is creating a "redundant" drive based on the primary (ropey sectors and all). RAID 0 should in theory be faster at reading than no RAID and will be faster than RAID 1. It may have been the move from IDE to SCSI (5400rpm to 7200rpm back in the old days) that increased the read speed of mpeg rather than RAID.

You've now got a handful of us running around trying to remember why we went RAID1 rather than RAID0 Somewhere 'round here is a box with all the system logs; which were kept religiously back then... A habit we seem to have lost... :blushing:

Yes; I think the faster drives had a lot to do with it (don't actually recall the spin speeds!); and that IIRC was the primary reason for SCSI being seen as essential. Remember a lot of this would have been pre-UDMA so IDE drives were non-starters for any sort of serious work at full frame rates.

It wasn't so much the read speed that was a problem as the write speed and the pressing need to avoid dropped frames on capture... It was common practice to defrag the drives and pre-allocate space before capturing. This wasn't MPEG either but MJPEG... with A/D conversion and frame by frame compression carried out by dedicated hardware; usually in the form of a card slotted into one of the expansion slots... Some cards even had the SCSI controller built right into them.

Most systems had a means of varying the compression ratio as well as frame size and rate (and thus the data rate). But if you were working with going back to tape as your goal then you were (working in PAL) stuck with 25 fps and some factor of what we'd now call 576i (there were a few)... So the goal was sustaned uninterrupted writing over a relatively long period; and I might be imagining it but there's a bell ringing somewhere that says that's why RAID1 was used over RAID0...

Preview playback was often diabolical; it was only when we invoked the 'print to tape' function (usually after rendering the finished piece and defragging) that perfect playback was really essential... And not always achieved either!!!

The fog lifted marvellously when UDMA drives and Promise controllers came along! :thumbup:

NOW! Cat's whiskers and valve radios; they were the thing.....:lol::lol::lol::lol: