Need advice on hardware? Ask questions and share your opinions here.
#794 by lmlowery
Sat Mar 05, 2005 8:56 am
Do any of you have any advice on a portable backup system? I am thinking maybe an external USB or firewire hard drive. I would like for it to be portable so that I can back up a couple of off site computers we have as well as the four we have at the office. I like zip drives too, but the only external one we have is not one of the newer ones. I THINK the one we have can only use the 100mb zip tapes.

Any advice or reccommendations would be appreciated!

I LOVE this forum!
#800 by Neil Blanchard
Sat Mar 05, 2005 10:55 am
Hello:

Here's what I would recommend: buy two external USB2/Firewire hard drive units, and rotate their use every week. Keep one off site for a week and then swap them.

Here is a seller with lots of choices (scroll down to the bottom of the page to get to the links for each brand):

http://www.newegg.com/app/manufact.asp?catalog=414&DEPA=1

They come in two basic classes: units that use a desktop 3.5" hard drive, and those that use a laptop 2.5" hard drive. Many have both a USB2/1.1 and a Firewire connection. USB1.1 is pretty slow, so the intial (big) backup would be pretty slow; but USB2 and Firewire are much faster.

They come in capacities up to 400GB -- these are about $325.

The best thing about these drives is that you can plug them into just about any computer: Windows, Mac, or Linux, and you can retrieve your data. So, they are relatively "future proof". They are reasonably portable -- a nice protective case/box would be smart; maybe even a fireproof one!?
#6853 by Neil Blanchard
Thu Oct 13, 2005 9:06 am
Greetings,

This is from a thread on the DBUG listSERV forum, that seems apropos here. Here's my post in answer to a question about RAID 1:

> Does a "mirror image" RAID setup make an exact copy of the primary drive[?] I have been told that it does so.<


Yes, a RAID 1 array, which uses two hard drives, uses one hard drive to boot from and then copies the entire contents of that drive to the other. If either drive fails, then you will see a warning about it during the POST -- but the computer will boot normally using the other HD.

To repair it, you simply have to replace the broken HD, and then go into the RAID BIOS, and rebuild the RAID 1 array -- you just have to choose the drive with the data on it as the source drive, and the replacement drive as the copy drive.

You can test this, if you like, by disconnecting the main HD -- with the machine off, off course! This will mimic a HD failure. Then see if the machines boots properly. Be *warned* though, you will have to "rebuild" the array as if the HD had actually broken; so you will have a "practice" run, as it were. This will take about an hour, if you choose to have the contents copied while in the RAID BIOS; less if you choose to have it (re)copy it in the background.

This is a very good method, IMO, since the user does not have to do anything special in order for it to happen -- it does so in the background. BTW, in Windows Explorer/My Computer, you only see one HD -- the hardware does the work to copy the contents of the drive "below" the level where Windows can "see".

But it does not cover all eventualities: if the data gets corrupted, for any reason *other* than a failure within the HD, then the corrupted data is copied to the other HD. The machine can still fail in a way that can damage both HD's, though obviously this is less likely that just one HD failing.

You should *still* do a *full* *data* *backup*, to at least another machine, and/or to an external HD. Another machine is good for failures of the entire machine, or for if both HD's fail, or if that machine gets stolen. You can use the data on the other machine right away after a problem.

The external HD is good for portability. If you use a pair of external HD's in alternation, then you can have most of your data -- all except the most recent stuff kept *off site*, in case of fire, flood, or complete theft. ZIP drives and/or CDR's can be used for current backups of working projects; but should probably not be used for archiving or long term backups. I think tape backups have gone the way of the dodo? In my experience, tape is hardly reliable to recover one or two files; let alone an entire system.

RAID 0, which is called "striping" and uses two (or more?), is not really redundant -- in fact you are at least *twice* as likely to *lose* all your data if you are using RAID 0; because if either HD fails, then you lose everything. Rather, RAID 0 is *supposed to be faster; but all info that I have seen is that any speed increase is minimal and only in certain fairly rare instances. It does "sum" the capacities of the HD's.

RAID 1 is mirroring, and it is the simplest method to get redundancy. You have to have (at least) twice as much physical capacity as you will use.

RAID 0+1, aka RAID 10 is striping & mirroring and uses four HD's. It combines the (supposed) speed increase of the striping with the redundancy of mirroring. You can use about half of the total capacity of the four HD's.

These three RAID-types are fairly common on modern motherboards and PCI controller cards. If you are building a new RAID array, you should opt for SATA or SCSI, since they have some important advantages over IDE.

RAID 5 uses three or more (up to five, I think), and it is the most secure, since it uses a full parity check of the data. If one of the HD's fails, then the data is able to "recreated" from the other disks. This is more common in SCSI RAID controllers, but is also available on some PCI SATA controllers; or possibly on high end server motherboards.

I don't think that RAID 2, 3, or 4, are actually used anymore; if they ever were.

Large HD's are relatively inexpensive, and we should not hesitate to use as many HD's as it takes to make our business' data as secure as possible. Would you rather spend $100-750 now, to greatly increase the safety of your data; or possibly lose *all* your data? A properly installed and cooled HD data backup is "a bird in hand".

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