Survey: Hot-Swap vs. Fixed Drives
 

Most posted configs don't have/mention hot-swappable drive capability, but I'm curious as to the realities that be out there, so please click away. Thanks.

I'm using all fixed drives at RAID 0.

Join the discussion
 

Paul,
There's a detailed discussion of the pros & cons of hot-swappable setups going on now.

Wow, submitted my vote in the poll and everyone agreed with me - "No, so far so good" or whatever it is - 100%!!! :) :D :cool:

...... and then I took another look - only one vote at that point ...... :eek:

Oh well, my wife's always telling me I'm 100%, now I can tell her she's right. :D

How would hot-swap save your bacon? If you have a drive die in a stipe you lose all, unless you are running 5 or 50 or one of the other generally not recommended RAIDS right?

Well, you're still in the vast majority, even if it's not 100%.

I know it's only been a few days, but I thought there might be more big-time pro's out there with hot-swaps. Maybe once they finish swapping . . . :D

AFAIK, if a drive takes a dirt nap, you can swap it out immediately. Yes, you'd probably have to rebuild the raid, if it doesn't happen automatically, but recovery time would be hours (if not minutes) and you could still get that Big Project to the client on time.

With a fixed drive system or hot-swap w/no spare drives (WHY?!?!?), you have to contact your favorite vendor and order a new drive. Overnight shipping is not instantaneous. Then you gotta pull your box apart and replace the drive. THEN you rebuild the raid. Meanwhile, your client is leaving you voice mail with FCC-unapproved language.

At least, that's what I think . . .

>>if a drive takes a dirt nap, you can swap it out immediately. Yes, you'd probably have to rebuild the raid, if it doesn't happen automatically,


I believe if you lose a drive in RAID 0, which is what Newtek suggests, then you lose all data. There is no rebuilding unless you have a back up.

I have 6 73GB U320 15k Seagate Harddrives, 1 73GB U160 10k Seagate, and 1 ATA 120GB Western Digital. 4 15k drives in raid 0, 2 15k drives in raid 0, 1 10k as system (c) drive, 120 ATA as storage. I lost a drive(raid 0) and all my files one time.

That is absolutely correct since in a RAID 0 configuration, you have no redundancy, you have data spread across 2 or more drives and the loss of one drive means complete data loss on the whole RAID.

I'd just like to say I know a 0 array is delicate, okay? If a drive goes bye-bye, your project won't fly and you'll sigh and cry. The client will moan when he's on the phone and castigate, excoriate and promise a horrid fate.

Seriously, since the RAID 0 array must be rebuilt from scratch, at least with a hot-swap system, you pop the old drive out, pop the new drive in and start rebuilding, instead of waiting for the FedEX/USP/DHL person and spending x amount of time and bandaids for your bloody fingers pulling your system apart to replace the drive.

I thought some levels of RAID had automatic recovery built in. I know RAID 0 is very simple but I thought there was a system option or 3rd party program that would automatically rebuild the array. I guess not. Oh, well.

RAID 3 and 5 offer the ability to lose a drive and keep on going. I don't remember the specific differences but basically, there are extra checksum bits stored on each drive. If/when a drive fails, the extra bits on the other drives can re-build the data lost on the failed drive. Of course, with these RAID configurations, you sacrifice speed and space to accommodate the redundancy.

Also, you need RAID controller for anything other than 0, AFAIK, which has issues of it's own...

I'm not sure why anyone would pay the extra money for a hot swap chasis. I honestly see zero advantage to having this in a video array. As previously pointed out, if you lose a single drive you lose the whole smash. Having an extra drive around would be nice and would avoid having to order one and wait, but hot swap capabilities are not necessary or even warranted. If you have an extra drive you can swap out, all you have to do is crack the case and switch it. An expensive hot swap chasis will only save you 2 minutes. It's gonna take a lot more time and money to set a hot swap chasis up in the first place.

A hot swap drive is primarily for redundant raids and interchangable storage, (swapping storage between two or more systems or alternating data on one system).

Note: The following statement has been IMMEDIATELY preceded by 30 seconds of loudly knocking on wood ! :p :D

My first VT system was built on the cheep (since I couldn't afford a full-blown unit at the time) and was configured with IDE drives. When Blaine built my Dreamstation, I did briefly consider hot swap drives. The added cost vs. the reliability of the IDE's that I had for over a year with VT[2] along with the advice that Blaine gave me about the different RAID configs and limitations steered me away from hot swaps and anything other than RAID 0.

Both the IDE and SCSI RAIDS are humming along smoothly. :cool:

Generally, I agree. Hot-swappable seems to be confused by some with fails-safe redundancy levels, but that is not the case.

As has been pointed out, unlike the other RAID levels, RAID 0 (while providing the blistering speed we all love to brag about) does not offer any level of securirty. From a security standpoint, it matters not a whit whether the striped drives are connnected in a hot-swap configuration or cabled in traditional fashion. Hot-swappable is simply a matter of different connnection, not different configuration.

That said, it does take slighlty less time to bang a hot-swappable in place -- maybe on the order of 1 minute to swap drives vs. 3-5 for a standard connection requiring you to open the case. I'd have to say Im skeptical that saving those 2 minutes would justify the added expense for most applications.

Interesting tidbit I ran across today, there is an XP hack for a couple of system files that enables software RAID 5.

Got a link?

There are some programs out there that will rescue you if your raid fails.

Winternals Software
QueTek Consulting Corporation
R-STUDIO- Data Recovery and Undelete Software

And i am shure there are some otherone aswell

Chribba

Google turns up a couple like:

RAID 5
RAID 5
RAID 5 without CONTROLLERS (Tom's Hardware - German to English)

Thanks Brad !!!

AFAIK there is no software that will save a RAID 0 with a totally failed drive. If you lose a drive you have lost part of your info. There is nowhere to go to rebuild or back it up from. If you catch the data before the drive completely fails then maybe, but once the drive is gone, so is the info.

I have not tryed ant of the programs myself i only read from their website...

Winternals Software
Disk Commander is a data-salvaging tool that allows you to access and recover corrupt or otherwise inaccessible files on NTFS and FAT partitions even if the disk has been reformatted. Disk Commander also repairs certain partition table, MBR, and boot sector errors that result from viruses, user errors, or system crashes. Disk Commander can also recover deleted files, even those not saved in the Recycle Bin. The ERD (Emergency Repair Disk) version runs from a set of Windows 2000/NT boot floppy disks and allows access to drives using SCSI or RAID devices, and to the Windows NT/ 2000/XP/Server 2003 volume sets found on many enterprise systems. It uses boot diskettes or a bootable CD-ROM created from a Windows NT 4.0 or Windows 2000 system.


QueTek Consulting Corporation
With File Scavenger™, files can be recovered from reformatted or corrupted volumes. This is even possible when a volume has been deleted and its original position and size are unknown. Using the unique "Defunct Volume Search" mode, File Scavenger™ can scan an entire physical hard drive to look for traces of defunct volumes. Also in this mode, files can be recovered from broken striped volumes (i.e. RAID 0 or RAID 5) or spanned volumes (volume sets) provided that the component physical drives are still accessible individually. (For striped sets with parity or RAID 5, one drive can be missing.)

File Scavenger™ has advanced algorithms to transparently handle disks with many bad sectors and badly corrupted partitions. The software can be installed on a hard drive or run from a floppy disk. To run File Scavenger™, you must log on as a system administrator to the computer where data recovery is intended.

R-STUDIO- Data Recovery and Undelete Software
R-Studio unformat tool can analyze and unerase data from software RAIDs and volume or stripe sets. R-Studio detects and processes hardware RAIDs and volume or stripe sets like regular drives/volumes. Hardware/software RAIDs can be searched for files or scanned. Found files can be recovered the same way as from regular drives/volumes.

If, due to data loss, a system does not recognize a software RAID, but such RAID did exist, and the information on what hard drives were in the RAID is available, a Virtual volume set or RAID can be created and processed like a real software RAID. Such Virtual volume set or RAID may also be used to unerase data from hardware RAIDs and volume or stripe sets if their controllers do not work properly.

If a partition from a hardware or software RAID and volume or stripe set is absent, due to hardware failure, for example, empty space may be added to the Virtual volume set or RAID in order to correctly re-construct its structure.

R-Studio unformat tool does not write anything real on disks. Empty spaces and Virtual volume set or RAID are pure virtual objects that do not affect actual data on disks.




Maybe you know more then what the information on the website's tells me but if my RAID went down and i needed help i will contact them to get information on however it is possible to get data back by using their program....

Chribba

>>>AFAIK there is no software that will save a RAID 0.. bla bla

Yea boy, it would be nice to be wrong about that!
I do know in the last 3 years dealing with the VTx, these forums and RAID 0 I have heard of or seen many users RAID0's go down on them and no one has ever mentioned trying to use or using a program to get it back.

It's always been lose a drive, lose your info.

Maybe there is hope.
Sure would be sweet.

Now who will be first to lose a drive and try it out?
:eek:

Thanks for the info!

Jim

OK, i will give this a try!, i actually have lost my drives i think :cool:

If no one can tell me how to get data back and get windows XP to recognice my "STRIPE" drive... The thing that happend was that i had a shoutdown when i tryed to help a friend to format his HD (that disc had some big problems). To be shure that nothing happend to my data on my swap disc's i took them out of my system.
This is what happend: Both IDE connectors went down and could not recognice any HD or CD.

When i finally got my own system to work again i put my swapdisc's back in ... but WindowsXP cant recognice them a STRIPE.. I thougt that i might put them in the wrong order but i have tested every way i see it. In Admin tools i can see the disc and the STRIPE but it wont connect them... So i have tested one of the programs to see if it can find any data on my STRIPE... It has, i can see everytning that was there, the only problem is that is has to have another drive to recover the files to... and now i have to backup another drive to get the amunt of space i need to recover the files... So far so good... Or does anyone know another way to help Windows to recognice the STRIPE??

chribba

Did you go into the Disk Manager and reactivate the disks?

I think that has to be done first, before the stripe set comes back....? It's been awhile since I had all my drive problems.

You should not have lost any data with what you did, it should be just a matter of getting the stripe set back.

Hopefully, you didn't delete the drive in disk manager.

Those software repair won't help your situation, AFAIK.

Yes i have tryed to reactive the disks, didn't help.. One thing i cant remember from when i did the stripe is if i should see the disks both as induvidual disks and as a stripe. And does it matter if the disks are in a diffrent order in my hotswap places..That confuses me a little.

chribba

In the lower window in disk manager where it shows the color bars representing each disk, you should see every individual physical drive.
There should be no bar representing the stripe set in this area. The individual disks will be numbered here. (Although if it is missing I believe I recall that it would generate a bar for the missing volume.)
In the upper window it should show things by volume only. There you should see V:, for example as a volume as a 68GB striped dynamic drive instead of four 17GB disks.

I also wouldn't think that they would have to be in the same order, because the order on the cable dosen't matter, just the SCSI ID number.
I assume you are using SCSI drives and a Windows software stripe, right??

Just wanted to inform everybody that R-Studio did recover all my missing files. To fresh your memory, i have a window striped volym with 4 36gb harddrives and something happend so i lost my volym and could not get it back. Trust me i had tryed everything there is, then i tested R-Studio and it did find the stripe, the only thing was that i had to recover the files to a new harddrive... But when it was done i had not lost any files at all, So i formated my stripe again and moved the files back to the stripe, and all is just great..


It was worth to try it :rolleyes:

chribba

You moved your data back onto the stripe that was failing? :eek:
Did you find out what drive is going bad and replace it? If not it will just fail again probably.

Yes software will restore a RAID 0 if you have not lost a drive. But if a drive had gone south completely no software will bring it back in a RAID 0.

Sounds to me like he lost the stripe set info when he removed his drives, rather than having a failing drive.
Perhaps the same drive letter was assigned to his friends drive when they put that one in and it overwrote the stripe set data for the drive he took out.
This would explain R-studio being able to recover the stripe set data.

Glad you fixed it and got your data back! Now do a tape backup, or a backup to another disk drive.

What I do, is incremental backups to a 300GB EIDE drive (fast) while I am working on a project, so if something happens during the project I still have a copy. Then, when the project is finished, I back up to tape (which takes much longer) for archive and then delete the files from the hard drive. I use Retrospect software for backup which allow me to go and recover a single file from the backup if I need to, without restoring all the data.

redundancy is for mission critical type systems ...
 

the technology is cool and advanced and most likely found on spaceshuttles and telecommunications equipment. The advantage is when you have a dual bus system so if the drive is the only thing hotswappable then it doesn't make a lot of sense and is most likely overkill. IF however the system is advanced enough to where it will have a mirror of the raid on a seperate "side" then theoretically the system is fault-tolerant and this could avert potentially EXPENSIVE downtime, etc. :cool:

Thanks to all who participated
 

Thanks to all who participated in this unscientific poll. Apparently, it's a 60/40 split in favor of fixed drives, at least among those who voted.

Speaking of which, I note the poll display says there were 25 voters, but adding up the votes cast in each category gives 27. Apparently, there's a lively VT community in Chicago. :D

now, we use a hot swap chassis for SCSI and SATA becuase it makes assembly and servicing easier. Instead of multiple cable and power connections, there is only one.

Still, there is no data protection. One thing we've done is use the IHCR-6 chip to do a RAID-1 as abackup drive that is internal.

RC4852 from RAIDCore

Blaine, it that something I can add to my machine?