Hitachi 1TB Hard Drive (and RAID discussion)

WHOAH. That is awesome.

 

Next week, I'll be replacing my internal drives with 1TB drives (4 of them). Being able to have 6 in there would be crazy, and could lead to some interesting RAIDing. I'd probably run a small striped partition for swap, and the rest of it as RAID 1+0 (per this suggestion).

Eric

Is there any reason why you're running software vs hardware RAID? I use a Attotech RAID card so I can clear the data overhead from the CPU, which will be busy enough with uncompressed work. My RAID card is this one. Apple has a new RAID card out that's twice as much. Also I hear there's a RAID card with a upgradeable ECC RAM chip that'll help in RAID 5.

Also are you running Linux? why do you need a swap partition? Or have they figured out how to get Intel macs to write to the swap partition and not fragment the whole boot partition?

Ok I'm totally geeking out here!!! Scary!

Wags, I still have my 40GB UWSCSI array from 1995. It still works.

I'm running software RAID because I have plenty of CPU power. No big deal. I'd only need hardware RAID for RAID 5, and I am not using that at the moment, except in my NAS boxes and servers.

I don't *need* a swap partition, but it can't hurt to move swap to a fast partition.

I use 6 750GB configured as 2 3-drive RAID 0's, then I configure SuperDuper to do nightly incremental backups. Should the boot array fail, OS X is capable of booting from the backup. To keep OS X from indexing the copy, I simply leave it unmounted. SuperDuper is smart enough to mount the partition and unmount it afterward. I still have to check the backup periodically to make sure it hasn't failed.

The advantages of that approach are a slight improvement in speed and a safety net should you lose or corrupt a file. The disadvantage is obviously that you have risk of data loss for any changes between nightly backups. You can always run a backup manually if you have data that you want mirrored immediately.

With Time machine it's not clear that my approach is really necessary since I'm primarily protecting myself from myself, but the manual mirroring approach also protects against OS failures and bugs. I find that OS X's implementation of file-based partitions acts weird over a network and I've had to rebuild those a few times. With RAID 1 I would have been screwed. Remember, RAID is not a substitute for a backup. SuperDuper is ;-)

It makes no sense to create an array, then partition it into two or more active partitions in hopes of improving performance. Specifically, creating a swap partition as opposed to putting swap on the main partition itself. All you are doing is forcing a mandatory seek distance instead of enabling the OS to optimize. It also doesn't make sense to swap to a redundant array but I don't have that problem. ;-) Good performance means enabling your system to find optimization opportunities. Hard partitions erect barriers and create configurations that are forcably degraded.

In a bug-free world, it may be more interesting to to run RAID 1 in combination with a RAID 0 Time Machine drive. Just speculating based on not knowing how Time Machine really works. :-p I know that Time Machine requires a separate partition but I don't know if the system can recover should that partition fail.

Finally, after having been a RAID firmware developer in a previous life, I can honestly say that I'd never use a RAID 3/4/5/6 product unless I absolutely needed to and, these days, drives are so big that most of us really don't need to. RAID 0/1 is relatively easy to implement and is fast. Parity-based RAID is sufficiently hard that most vendors are incapable of doing it right. I know because (1) I was responsible for some eye-opening bugs myself, and (2) I did dozens of competitive evaluations and not one products worked when trouble started. I've owned plenty of RAID products other than my own, and the few times I needed them to work they always failed. No need to use parity drives when the system will lose data in any case.

Remember, redundant RAID levels are needed when the system absolutely must continue to run in the event of drive failure. Few of us actually need that provided we have an effective recovery mechanism (which Macs particularly do, I love that!) since all we risk is the work we are currently doing. Considering that many of our systems lack sufficient redundant hardware, we are fooling ourselves in believing that RAID actually buys us much. How many RAID users consider just how many different kinds of failures their systems can actually tolerate? If a drive failure costs you a half day or day to recover but otherwise results in no data loss, isn't that good enough?

I use 6 750GB configured as 2 3-drive RAID 0's, then I configure SuperDuper to do nightly incremental backups.

I do a varitation of the same theme - basically either Retrospect or SuperDuper or other utlility to back up data that I do not want to lose and then keep one copy of the data somewhere else in case of fire etc.

I use the RAIDs for speed :-)

I don't do remote backups since I don't run a business off my data, but if I did I'd do exactly as you describe. Hard drives are simply too fast and too cheap not to use in that manner. :-)

I absolutely love the combination of SuperDuper and firewire boot. Replacing a boot drive in a Mac is laughably easy. :-)

Have any of you given thought to Time Machine yet? It seems like a compelling feature although I don't know how effective it will be for databases and I'm a bit concerned with stability. How will you set up your drives to use it?

I have found that backup solutions on the Mac are lacking. SuperDuper is great (I use it) but it doesn't version my files. I want somethinglike Retrospect that can version my files, protecting me from corruption and from myself.

All of the backup software I've tried on the Mac that support versioning are terrible. Maybe time machine will just solve all my problems.

Oh, and about the partioning thing: I like having a separate system partition so I can reinstall from scratch without touching my data. On Windows, this was an absolute requirement. Maybe I am thinking with a PC brain...

Have any of you given thought to Time Machine yet? It seems like a compelling feature although I don't know how effective it will be for databases and I'm a bit concerned with stability. How will you set up your drives to use it?

I am not sure quite how I will use it yet.

Usually though with any updates to OS or other software I take a very conservative approach in bring the items on line. First I go by the principle if it ain't broke don't fix it - meaning unless there is something that has developed as a conflict or will not run on my production machine, the machine does not get touched.

Then I start putting things on my other machines, including an old iBook, tiBook or MacBook Pro to see how it works and get the feel for the new software for a bit and see what issues exist.

Then I will put in another hard drive or boot external boot drive for the main machine I use. My main boot drive on my tower is still 10.4.5 and I have no real compelling reason to change it. I have 10.3.9 and 10.4.9 on another drive on the machine when I want to jump to an older OS or run the new FCP Studio 2. (As an aside I also do what Eric mentioned, I make a disk image of my clean installs in case I ever need it. There is a back up image of 10.4.9 with FCP Studio and nothing else on it.)

At this point though I guess I am pretty much Tiger and have not gone back to Panther in any form for quite awhile.

As to the Time Machine feature, I will go with the wait and see tatic for a bit. I am used to doing what I do now in terms of back-up and it has served me well. I walk away, watch some tv or something and things are taken care of and it is been reliable.

Guess that is a long way of saying I am scared of all these new fangled thingies It is has been years since I have had an issue (a Jaz Drive and some LaCie Drives) so alot of what I do is just by rote and what I feel comfortable with.

Eric have you tried Retrospect for the Mac yet? It is pretty good. The one thing I also do is label each file/project/version like 20070825_Film so I can do a search and know I have different versions.

Wow, it must be nice to not have problems. Out of 6 750GB's I've added to my Mac Pro, one is already dead after a month. I've mailed one MBP in once and another 4 times in the last year, replaced two failed boot drives in additional systems and lost a notebook DIMM. I'm on my 3rd router in the last year as well. I don't consider this year to be much different than others (except that it's mostly Mac now). Failures are common for me.

What does versioning within a backup application offer a home or small business user?

Finally, after having been a RAID firmware developer in a previous life, I can honestly say that I'd never use a RAID 3/4/5/6 product unless I absolutely needed to and, these days, drives are so big that most of us really don't need to. RAID 0/1 is relatively easy to implement and is fast. Parity-based RAID is sufficiently hard that most vendors are incapable of doing it right. I know because (1) I was responsible for some eye-opening bugs myself, and (2) I did dozens of competitive evaluations and not one products worked when trouble started. I've owned plenty of RAID products other than my own, and the few times I needed them to work they always failed. No need to use parity drives when the system will lose data in any case.

 

Remember, redundant RAID levels are needed when the system absolutely must continue to run in the event of drive failure. Few of us actually need that provided we have an effective recovery mechanism (which Macs particularly do, I love that!) since all we risk is the work we are currently doing. Considering that many of our systems lack sufficient redundant hardware, we are fooling ourselves in believing that RAID actually buys us much. How many RAID users consider just how many different kinds of failures their systems can actually tolerate? If a drive failure costs you a half day or day to recover but otherwise results in no data loss, isn't that good enough?

Oh great, now you tell me my RAID card is just sucking electricity for nothing. Ah well

Actually my workflow uses RAID 1. My boot partition is RAID 0 which has the apps partition, All my apps write data to the RAID 1 partition (whatever app files so it's backed up). The boot partition is hardly over 100GB with various software.

I hate that VM files fragment the disk (even if OSX defragments the files) so that is why I asked about the SWAP partition. On the G4/5 computers, there were ways to set up a SWAP partition so VM files are written to that partition only. The drives stay less fragmented vs a single boot partition. Last I looked MacIntels have a different boot system that precludes this but if Eric has found a way, he MUST SHARE!

Craig, even if you don't run a business, you do spend a lot money getting those images and in the unfortunate event of your on-site drives being lost for whatever reason, an offsite system is a great safety tool which saves the day. Maybe it's a Californian "watch out for the big earthquake" mentality, but off site is a good buffer. My offsite is on another continent.

As for your hardware failures, there's been a belief that some people have the inate ability to cause electrical failures more than usual. Something to do with the energy field they emit Maybe you work em too hard too.

For using rsync to simulate Time Machine, this guy has a script.. I haven't tried it yet because I only backup once a week for the boot partition since the data files are already backed up.

Are you all using Leopard already? I didn't find it too stable and decided to can it a few months back. But my build was at least 7 months ago. Too lazy to get updated. Anything new?

Wow, it must be nice to not have problems. Out of 6 750GB's I've added to my Mac Pro, one is already dead after a month. I've mailed one MBP in once and another 4 times in the last year, replaced two failed boot drives in additional systems and lost a notebook DIMM. I'm on my 3rd router in the last year as well. I don't consider this year to be much different than others (except that it's mostly Mac now). Failures are common for me.

 

What does versioning within a backup application offer a home or small business user?

Sounds like you got hit with a rash of things. I have had some things go wrong of course over time. One iBook issue, one G4 processor and couple of other things. On the hard drive side of things have been pretty lucky (except for Lacie Drives) and one or two casings which had bad connectors/wires and one that had an intermitent power supply issue (that one was really weird). But no data loss (other than the Lacie but they were also backed up.) But all of these were over the last six years or so. The power adapter and the loose port are the only two things I can think of in the last year.

I have had pretty good success using Seagate Drives the last few years, have been reliable.

Was not sure if you were speaking to what I described in versioning 20070827_V1_Film etc. but with many things I am adding and modifying as I go along. Depending on what it is (documents, photos, film) I need to either specifically refer back to other versions and also once in awhile a file will become corrupted. So saving periodic versions can save a lot of time if I have a file go bad. Fortunately that has not happened in quite awhile. Also for some things I set up a "base" version of a project then try alternate versions or ideas which may or may not be what I want down the road. So starting from a base that is 70% of the final idea as oppossed to rolling back a project can be helpful. And sorting by thiss naming convention helps in the Finder.

Again alot of this depends on what I am doing.

I only use Seagate and Hitachi now. Although.. a friend ordered 4 1TB Hitachi drives, and three of the four were DOA (!).

Re: file versioning: I've had files get corrupted and had to go back to retrieve the ones that were still intact. Because I hate Retrospect for the Mac (see below), I no longer have versioning. It's been scary. Who knows what has been corrupted and backed up? You can't test all your files.

As for Retrospect on the Mac, the reason I don't use it is that it's 3x slower than Retrospect for the PC was when copying over the network. I am on gigabit, and my Retrospect backups clocked at 4-6 MB/s. Pathetic! When copying in the Finder, I get 30+ MB/s.

Also, Retrospect for the Mac is a pathetic excuse for an application. The application itself is a piece of crap, even though it probably works.

Actually, all of my backup programs on the Mac run really slowly when not targeting a local disk. I have tried almost all of the backup programs out there on the Mac, and they're all 2-3x slower than what I used to get using PC-based programs. It's no big deal if you're copying a couple hundred GB, but when you get up in the TB range, a slow network is death.

Those of you on Windows should check out SyncBackSE from 2BrigthSparks. A software developer friend whom I trust swears by it.

Actually, I was only speaking of parity RAID, RAID 0 and 1 are fine. Thing is, if you aren't doing parity you don't need RAID hardware. If you have some much data and performance requirements that dedicated hardware is needed, then that's another matter. Sometimes storage appliances make sense.

As a RAID engineer for almost a decade, what I learned is that parity RAID is the work of the devil. Actually, what I learned is that you don't want to do RAID at all, the best place for it is in the filesystem. End users can't influence that though, so RAID is what we get. The last place I worked was a startup intended to replace RAID with something much better. It tied its fortunes to Infiniband and became something I didn't want so I backed out. There are much better ways to store data than RAID!

I didn't mean to denigrate offsite backups. A compelling case can be made for those, I just don't do them. :-(

No, I'm not running Leopard. I'm too new to OS X and not sufficiently curious. I believe Time Machine could be interesting and useful though. Oddly, back in the VMS days I found automatic file versions to be an annoyance. Now I want it.

I wouldn't say I've had a rash of failures. Hard drives fail for me all the time. My original MBP was an early model with lots of issues. A later MBP was shipped to me defective. The rest of the failures are hard drives and memory, though out of the 8 Mac products I've owned 4 of them have had failures that required warranty service withing the first month. I'm not convinced that the hardware reliability of Macs is worse than PCs but I'm not convinced it's better either. I'm still happy with the conversion.

Regarding Macs and network performance, I suspect trouble there. Panther's network performance was terrible and Tiger's Samba performance is too (surprising since Samba generally works well). My Macs share pretty well over wired but mounting filesystem images over wireless seems to corrupt them. Copying data from a Mac to a PC over gigabit (via Samba) yielded only 8 MB/sec for me. Whenever I get a lot of network traffic going my Mac Pro beachballs like mad despite virtually no CPU usage. It used to be that OS X had only a few spinlocks for the entire kernel. That's supposed to be improved though how much I don't know. On my old dual G5 running panther, two simultaneous network copies would lock out the entire machines. I eBay'ed it. I wonder if backup performance over a network isn't Apple's fault especially if the network devices aren't also running OS X.

I wrote a lot about slow network performance between Macs and Windows. Here's how I fixed it:

http://echeng.com/journal/2006/09/13/mac-o...-to-windows-xp/

I find fast traditional copies over finder / explorer, but really slow performance when going through every program out there that does file compares / copies.

Do you believe then that slow network performance within apps is another problem or simply an indicator of an incomplete solution? Do you get slow app performance with networks FS's other than SMB? Considering that Finder and Explorer are just apps I'm intrigued. I was discouraged by the slow performance between OS X and Windows and it delayed my adoption. Once I replaced my HTPC's with Minis things got a lot better. I was dumbfounded that GigE seemed useless.

It's easy enough to disable IPv6 in Windows without using the command line. Why did you find that necessary?

Anyway, I've included the changes you've recommended even though I have little need at this point. It would be nice to get better than 8GB/sec next time I copy my 200+ GB iTunes library to someone's Windows box. :-)

Hi Mods,

This is an interesting thread with heaps of good pointers about networking and RAID - any chance of splitting it into a new topic?

As for Retrospect on the Mac, the reason I don't use it is that it's 3x slower than Retrospect for the PC was when copying over the network. I am on gigabit, and my Retrospect backups clocked at 4-6 MB/s. Pathetic! When copying in the Finder, I get 30+ MB/s.

 

Also, Retrospect for the Mac is a pathetic excuse for an application. The application itself is a piece of crap, even though it probably works.

Yeah it can be slow even on local drives, since using eSATA not quite as painful, and have gotten fairly decent speeds, though I do not have the backups via a network. Guess I am used to backing up the Macs this way so overlook the issues to some degree. I actually have a copy of ProSoft Data Backup that came with a recent hard drive purchase, but misplaced the disc. Was going to try it out and see how it goes (If I find the disc). Will let you know how that goes (unless you have tried it and can warn me not to bother )

Hey guys. I'm going to change the subject line of this thread to include RAID and networking.

I just implemented the 6-drive internal setup:

http://echeng.com/journal/2007/08/30/6-ter...s-in-a-mac-pro/

I'm back in business!

You beat me. I'm doing the same but I have to migrate drives in and out of the chassis so it's taking me more steps. Eventually I'll have an 8x750 arrangement.

Being relatively new to Macs, I have a couple of requirements. First, I have sensitive files that I want password-protected beyond login since I have guests who frequently help themselves to my machine when they come over and I'm not good at logging out. Second, I keep applications that I've downloaded so that I can install them on new machines and I don't want OS X to find them and install them in context menus (pinwheel city). My solution is to use mountable files for both those problems. That facility provides encryption plus I can leave them unmounted. Trouble is, OS X is constantly corrupting those files (I think because I access them over wireless). Until I figure out how to stop that, I can't commit to RAID 1 since corrupting one of those files means losing everything in them. I don't have a separate backup scheme nor do I want to have to use one every month to compensate for OS X bugs.

How do you guys archive downloaded apps and installers. How do you use encrypted filesystems? Anyone having these corruption issues other than me?

Hey, Craig. I just tell spotlight not to index my downloads directory. It is automatically backed up via Chronosync to a directory on a NAS box, which is mounts and unmounts as necessary.

My sensitive files are located in an encrypted, password-protected sparse image that lives in my filesystem. I haven't had a problem yet with corruption, and it is on a striped volume.

Btw, I did it so fast because i have superduper backups on external drives. Luckily, I didn't have to swap anything in and out, but I did have to go to the store to replace a 1TB drive that was DOA.

Um. did we lose everyone else? i'll bet most people are saying... "WHAAAAAAAAAAAAAAAAAAAAAA? I just want to take pictures!"

Um. did we lose everyone else? i'll bet most people are saying... "WHAAAAAAAAAAAAAAAAAAAAAA? I just want to take pictures!"

Eric, EXACTLY......., but I was thinking I just want to be underwater taking pictures!!!!!!

Unfortunately we can't set this stuff up underwater..........

Carol