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Hot swap RAID solution

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June 9, 2008 12:05:44 AM

I have a question similar to this http://www.tomshardware.com/forum/169530-32-sata-raid-mirror-swap

I have a client that prints fine art from files that have been scanned in to a hard drive. It is not your normal setup, some of these images are huge png files that can reach half a gig. Most will stay in the 120 to 150 meg range. They want a backup of these images that stays fairly current and readable. After looking at NAS and other ways to go about it I know what I would like to do but would like to know what kind of problems I will run into. They don't want an on-site admin and I would like it to work without a phone call every time they swap a drive out.

I think in theory the best thing would be a hot removable drive off of a sata RAID controller running a RAID 1 or mirror I can depend on. I would like to use 3, 1tb drives, 2 hooked into the array full time. Swap the mirror drive out on scheduled times and keep it off site.

Things I am having problems with are one computer they are running has a Asus p4c800 Deluxe board in it with a promise SATA1/2 378 controller. It has the ability to run RAID 0 or RAID 1 but I have read problems about using it. I want a controller that will work with that boards PCI slots that will not hiccup when you swap the drives out. I would like to know how long the rebuild will take, and wear and tear the drives will face over a sustained weekly swap where they have to rebuild the array. Run one drive where it keeps current all week then swap it out and store it with the drive that was stored. Rebuild that mirror to new then run for a week or possibly two making a judgment call on the amount of files that have changed then swap the drives again.

I think I would set all three 1TB drives up as data drives. No OS. Just mirrored NTFS data drives. I have thought about running the drives in a external box that runs its own controller and the mirror and drives are external from the machine. I wonder about speed when accessing files in this case. While in simple things the speed difference might be negligible when you are pulling 200 meg files it may not. We have ran scanners that use firewire an come to the conclusion that SCSI2 is much faster. I have no idea what USB 2 would do.

I also worry about corruption in the raid. RAID 1 is all about fault tolerance of the drive itself right? So if something weird happens saving the file but the drive is working properly the corrupt file will be mirrored and then passed on thru the back up process until you try and open the file again some day right? Is there a way to watch for that.

If you ran an external box would it be better to run a internal card and run the sata connectors out the back of the CPU box to the external drive case. Do they make a external drive case that will connect straight to SATA2 or do they all do the USB firewire thing. Or would the speed of USB 2.0 be sufficient.

In theory I want them to swap a drive out Friday evening when they go to play golf and everything be ready to roll the following Monday. I would rather look at replacing drives every so often compared to the time spent with other media. I want something that can easily be carried off site or put in a small media safe for storage.

More about : hot swap raid solution

June 9, 2008 2:15:32 AM

RAID 1 is not backup. You want backup, not RAID.

RAID is an availability solution. It is meant to keep a critical server or workstation running when a drive failure occurs. It is not a backup solution.

You need to look at a solution that does backup to disk. If it's just this one workstation that needs to be backed up, you could put the backup drives (all of them) in the workstation, and use some backup-to-disk software that runs every night and backs up the necessary files to the backup drives.

Having the backup drives in another machine on the network (like a network server) would also work. Map the drives on the workstation, and use the same backup software to backup the necessary files to the network drives.

These solutions are true backup. They maintain previous copies of the files in question. They are offline, so they are not exposed to viruses or accidental file deletion. Single-workstation backup software like this is relatively inexpensive. And with the disk-based backup, the users at the site do not ever have to change a drive or tape. The backup just runs automatically.

Do not attempt to use RAID 1 as a backup solution. That is not what it's for.
a c 156 G Storage
June 9, 2008 2:38:17 AM

EDIT----SomeJoe7777 beat me to it. Guess thats what happens when you game and post.

It looks like all you want is a backup. You can get external drives running E-SATA(this is the external sata connector you asked about) But raid is made for redundancy/speed(not RAID0 it has NO REDUNDANCY) not backups.

Are all the files kept on one system and the other drive is just backup or is it also used on the go? If its just about up to date backups there is a software called Second Copy that can do it automatically for you. Since it only copies changes, old files do not have to copy over and over again. This makes it fast and better for the drive. It can also keep old files and edits as well as work on networks too.

http://www.centered.com/
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June 9, 2008 3:24:01 AM

nukemaster said:

It looks like all you want is a backup. You can get external drives running E-SATA(this is the external sata connector you asked about) But raid is made for redundancy/speed(not RAID0 it has NO REDUNDANCY) not backups.

Are all the files kept on one system and the other drive is just backup or is it also used on the go? If its just about up to date backups there is a software called Second Copy that can do it automatically for you. Since it only copies changes, old files do not have to copy over and over again. This makes it fast and better for the drive. It can also keep old files and edits as well as work on networks too.

http://www.centered.com/


This is more what I was looking for so I am glad you did answer. I know what RAID is built for. I was not referring to a striped array. What I am wanting is a drive that stays current with the drive in use. I dont want them running most backup software. The majority of software I have dealt with is on servers and has to do with tapes. I was wondering if they there was something written out there for a incremental no compression back up to a sata drive. I have to many people think they are backed up who do their own. They will mess it up one time and be backing up a single directory or worse. In fact I don't want these guys having to do much of anything. That is why I thought I might run a mirror with another drive that was never more than a week or two behind. The only thing that bothers me about that is wear on the drives. That and if they got hit with power I could suddenly be down to one good copy. That software might work however. I could treat it in the same way just add a step at the end of each day. Then swap the drives weekly for off site safety. I had been looking at several products like Icy Dock and thinking of a way to stay current without burning the drives up with use.

Thanks

a c 156 G Storage
June 9, 2008 6:24:35 AM

Grab the trial(its 30 days) and try it out. If it meets your needs its not that expensive(i think i payed 30USD for it)

A hard drive does not burn up with use. even 24/7 most drives last 5 years or more. Hell i have a 15 gig maxtor(old maxtor before they sucked) thats still kicking and its been through systems and even used for data transfer.

The idea here is one copy in the machine and another copy on a drive you store off site. Update as often as you need. Hell even a drive for every day of the week. That would give you the ability to recover a deleted file up to 7 days later(but that may be over kill). There are many options for data backups.
June 9, 2008 1:30:26 PM

What I was afraid would burn them up was rebuilding that mirror each time I swapped out. I beleive the raid 1 would just completely rebuilt the hard drive. to just copy the files without a incremental backup software you would have to format the drive and copy all info from one to the other. But the ability to replace only the files that have changed or are new is wonderful. Any suggestions on a external drive enclosure that has hot swap drives? Will the software and the bios of the machine see the different drives differently if they are setup the same way??? Many of the boxes I have looked at dont say they support 1tb. Sata2 750 is about the biggest I have seen. What I am curious about is if the backup software willl know those drives have been swapped.

It has me thinking that if I can alter the times that it does the backup I could build a NAS box with swappable drives and have it do its thing at night. Or possibley just have it do it each weekend with a different drive. Keep the box unplugged 5 days out of the week. Let it just run on weekends. Losing a week of data would be nothing. It is that some of this stuff goes back 10 years and can not BE replaced. We have a lot of that burned to DVD. But we want something that can be access quickly and be back up and going.

Just a quick question. You know how there are tons of music programs to help sort and file music where it can be found now. Is there a professional software that keeps up with imgaes. The problem is there are three people who deal with these images constantly and they all seem to have there own system of filing. I need something that would pull those three people together. One does the images by date, another by name. I think it is more of a sit down and agree problem than something software can cure but a good library software made for images would be cool.
a c 156 G Storage
June 9, 2008 4:03:47 PM

I forgot to mention. make sure your back up drive(s) has a letter that will NEVER be taken by a usb stick or other device(make it Z or something). Be cause most software goes by the drive letter. This has happened to me a usb stick is plugged and pushes the backup drives letter(since its off when not in use windows just gave out its letter). Bang backup error, drive not found. Worse yet you could over write a usb stick(if it was ever beg enough for the job). There is a option to only back up if the drive label matches. You cam use this to make sure the right drive is in at the time of backup.

Now onto sorting. Windows has built in basic sorting for alphabetical(sort by name), Size, Type(all jpg's together ect, useless for you, but its there) and date last edited/created(modified). Vista has even more i think(on XP now so cant check).

Adobe Bridge also can do this(among other things and should come with Photoshop CS2 and 3, i assume you guys use that), but since your files are so big, anything running thumbnails can get slow.
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