Hitachi 1TB Hard Drive (and RAID discussion)

[Guest echeng]

For those of you thinking of setting up fancy RAID setups, Time Machine may not work for you. On my Mac Pro, Time Machine freezes when it starts looking for volumes, and then crashes.

 

I have been using CrashPlan, which is excellent. It's like Time Machine, but it only works across the network (local network when you're at home, and remotely when you're away).

[ChrisJ 0]

One good thing about RAID 0, is it speeds up I/O out of your Harddrive.

 

For Videophiles, it is great for encoding/editing/burning videos.

Edited December 3, 2007 by ChrisJ

[hoovermd 0]

I know this thread seems to be concentrating on disk drives both JBOD and various flavors of RAID but...

 

I get the sense from reading tis that these drives are being used for archive as much as "backup".

 

It is important to have your data secured but the various flavors of RAID all have significant limits. My personal favorite is RAID 1+0

 

From wikipedia:

 

RAID 1+0: mirrored sets in a striped set (minimum 4 disks; even number of disks) provides fault tolerance and improved performance but increases complexity. The key difference from RAID 0+1 is that RAID 1+0 creates a striped set from a series of mirrored drives. In a failed disk situation RAID 1+0 performs better and is more fault tolerant than RAID 0+1. The array can sustain multiple drive losses as long as no two drives lost comprise a single pair of one mirror.

 

However off-site tape backup is just as important.

I may be preaching to the choir here, but what if your place burns to the ground? Are you sure your data safe?

 

Is anyone else out there using LTO tape drives? I've got a Quantum LTO2 drive that stores 200Gb native at up to 123 GB/hr. Not as giant as a 1TB disk, but the tapes are easily stored at the bank in a safe Deposit box...

[craig 0]

A little history lesson regarding RAID 1, RAID 1+0, and RAID 0+1.

 

In the beginning there was the Patterson RAID paper. Prior to that, there was data striping and simple mirroring. There were no compound RAID levels. There was only RAID 1 through 5. All RAID levels implicitly included data striping. Without it, there could be no "redundant array of inexpensive disks" to replace a single, large, expensive one. RAID 1 encompassed RAID 0+1 and 1+0 from the beginning.

 

When the first RAID products were introduced, there were smart engineering teams and dumb ones. The dumb ones implemented simple mirroring, sometimes on top of data stripes and sometimes only in drive pairs. The smart teams (that would include my team) implemented redundancy underneath data striping because that was the right way to do it. We did RAID 1 right before doing it was cool.

 

When the dumb people realized that they were stupid and their competitors were smart, they didn't simply fix their own shoddy products (ever), they decided instead to "invent" new RAID levels. After all, one of them had already "invented" a non-standard RAID 6 that encompassed no more than heterogeneous hardware in a RAID 5 configuration. It was stylish to claim that you had invented new RAID levels, so it was no big deal to claim that RAID 0+1 and 1+0 were new levels because it allowed the idiots to claim that their product fixes were really new inventions. Never mind that Patterson's RAID 1 already encompassed all that... On the bright side, we got to add new RAID levels to our marketing sheet without changing anything in our product.

 

There is no RAID 1+0 and 0+1, there is only RAID 1. Any company who claims otherwise, and worse yet allows you to choose, you should run from. Sadly, all companies are forced to claim now that they support these ridiculous RAID levels. The ones that offer configurations that make absolutely no sense don't deserve your business. RAID implementations are surprisingly difficult to get right, so it's important to not use configurations more complicated than you need. Ruling out providers that indicate through their marketing that they don't understand RAID is the first step in that process.

 

Regarding TimeMachine, I purposefully haven't upgraded my main machine to Leopard because I suspected that would be true. We already knew that SuperDuper was broken and I didn't trust Apple to get TimeMachine right at first ship. Leopard is pretty much a fluff upgrade as it stands now. TimeMachine is the feature I want.

 

Mark, you can store disk drives in a safety deposit box too

[hoovermd 0]

Mark, you can store disk drives in a safety deposit box too

 

I do also, but most don't

Nice thing about removable mirrored drived is you can grab one, take it offsite and pop in another drive and rebuild the set.

 

 

I won't dispute your RAID information but if you want to run level 10 you better get the right controller card.

 

I would be interested to hear how many folks actually move their data off-site, how and how often.

[craig 0]

I won't dispute your RAID information but if you want to run level 10 you better get the right controller card.

 

I agree. In my years of developing RAID products I wrote a lot of testing software and evaluated a lot of competitive products. Virtually none of them could complete one of our stress tests and none survived our data integrity testing. These weren't all no-name products either---they included Compaq and IBM among many others. As years went by after my change in career, my friends continued with RAID and told me repeatedly that things never got better. I don't trust RAID cards because I know how bad they are and how hard they are to get right. Now that they are commodities I trust them even less.

 

That said, RAID 1 is a whole lot easier to do than any parity scheme. Anyone who trusts their data to RAID 5 had better have a very well-reasoned justification for doing so. Disk space is just too cheap these days to continue avoiding mirroring and on-line backups. I fully support the use of RAID 1 when you need it. I groan when people recommend RAID 5.

 

The proper way to do what RAID provides is to integrate it into the filesystem. Novell did this in Netware 3 and it was impossible to outrun Netware with RAID instead of JBOD. I know because we tried really hard. ZFS is a step in the right direction and I'm pleased that Apple has moved to integrate it into OS X. Still, ZFS has made some disappointing restrictions.

[hoovermd 0]

RAID1 is da-bomb!

I recently did an "old school" Oracle implementation using 7 spindled mirrored.

This is the absolute best compromise in my opinion albeit at the expense of space.

 

Check out the Dell MD1000 enclosures. 15 drives to a max of 1Tb each.

[loftus 42]

This looks really nice. If it works as advertised with Time Machine then nothing could be simpler. I wonder if one will be able to add more drives?

http://www.apple.com/timecapsule/backup.html

Edited January 16, 2008 by loftus

[PriusDrIVER 0]

This looks really nice. If it works as advertised with Time Machine then nothing could be simpler. I wonder if one will be able to add more drives?

http://www.apple.com/timecapsule/backup.html

 

If you check the tech specs page it appears the answer is yes:

"USB port for connecting a USB printer or USB external hard drive"

 

I have one on pre-order right now. I'm accepting that performance on the drive isn't going to be outrageous and it will be really just for backup, as right now my Time Machine drive isn't large enough to protect my internal drive and primary FW800 portable drive.

 

I have given up on performance on "home" NAS and can't justify the price of NAS that performs, so I am settling for simplicity.