Good point; ideally, one has both, but I'd also rather have a several-hours to 1 day window w/o complete backups than a complete mess due to corruption.
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Please critique: My plan for configuring 4 hard drives in Mac Pro
- Thread starter jasone6
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Good point; ideally, one has both, but I'd also rather have a several-hours to 1 day window w/o complete backups than a complete mess due to corruption.
Oh, and make sure to check out this website .
Wow thanks for starting this thread. I'm planning something similar.
Only I was planning on striping 4 drives internal and then using an eSATA enclosure externally to back up to 4 separate 1TB drives.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817332013&Tpk=t4s
(Backups don't need to be as fast as the system drives for me so I have no intention of RAIDing any of them.)
After reading through this though I think I will wait for Snow Leopard and see what Z Raids look like. I am waiting for the new Mac Pro's anyway so it looks that that will all happen around the same time.
Thanks for the in depth responses to jasone6's question.
Only I was planning on striping 4 drives internal and then using an eSATA enclosure externally to back up to 4 separate 1TB drives.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817332013&Tpk=t4s
(Backups don't need to be as fast as the system drives for me so I have no intention of RAIDing any of them.)
After reading through this though I think I will wait for Snow Leopard and see what Z Raids look like. I am waiting for the new Mac Pro's anyway so it looks that that will all happen around the same time.
Thanks for the in depth responses to jasone6's question.
I wouldn't stripe without mirroring and I wouldn't do anything without a backup....
S-
The main problem I see is that if disk 3 or disk 4 has a hardware failure then you lose both your system and your Time Machine backup (stripes require all members to be available). The disk 3/4 stripe array should be dedicated to Time Machine. This means the disk 1/2 stripe array should contain system+scratch+userdata. There is little advantage to having separate system and scratch partitions on the same disk performance-wise, and Time Machine excludes scratch files by default. I would make the disk 1/2 stripe array one large partition. Another factor is that journaling is the default these days, so a system crash will VERY rarely corrupt a disk partition.
There is one disadvantage to having a single huge disk partition which I recently discovered when I tried to copy my 1TB Time Machine disk. The directory information was larger than 4GB, which means that all disk copy utilities I tried could not copy it because they are 32-bit applications, which are limited to 4GB of virtual memory. Right now this should only be a problem on the Time Machine disk because it has many copies of the directory structure. If you anticipate having a LOT of files and/or directories it would be safer to have two partitions on the disk 1/2 stripe array: system+ scratch, and userdata.
There is one disadvantage to having a single huge disk partition which I recently discovered when I tried to copy my 1TB Time Machine disk. The directory information was larger than 4GB, which means that all disk copy utilities I tried could not copy it because they are 32-bit applications, which are limited to 4GB of virtual memory. Right now this should only be a problem on the Time Machine disk because it has many copies of the directory structure. If you anticipate having a LOT of files and/or directories it would be safer to have two partitions on the disk 1/2 stripe array: system+ scratch, and userdata.
Thanks Bob... I see your point re: Time Machine and system being on the same disk. I hadn't thought of that before... and in fact, I was trying to keep system and data separate per the research I'd done over at macperformanceguide.com.
Let me just see if I understand you correctly:
- disk 1+2 would be a striped RAID (RAID 0), configured as a single, two-terabyte partition. I'd have scratch, system, and data on this 2-disk volume.
- disk 3+4 would be a striped RAID (RAID 0), configured as a single, two-terabyte partition. This 2-disk volume would be used for Time Machine.
Is that what you're saying? If so, don't you think there'd be an advantage to making a 2nd partition on the disk 1+2 volume? In other words:
Disk 1+2 would have a 64 GIG partition for "scratch" space (utilizing the outside of the disks)
Disk 1+2 would have a second partition (~2tb which would include both the system and data).
Disk 3+4 would be a single partition set as a Time Machine backup for the system/data partition of drives 1+2
The reason I ask is that I know I want the "scratch" space to utilize the absolute fastest part of my disks (again, per macperformanceguide.com ).
Thanks for all the input!
-J
I guess the performance benefit really depends on what kind of files will be on the scratch partition. And note that any activity on the system partition will drag the access arm away from the scratch partition. Another consideration is that some day you might run out of scratch space (eg. doing a huge sort or working with HD video), whereas with a single partition all free space is available as scratch.
Are you planning on running Windows in Boot Camp in the future? FYI, Boot Camp doesn't support RAID configurations:
http://support.apple.com/kb/HT2855
(but you could run Windows under VMWare Fusion without Boot Camp)
I wouldn't mirror a stripe, but neither would I use it as storage or backup
.It really depends on how someone wants to use his computer; for me , everything internal is just for system, apps (1 drive), and then performance (all other drives, scratch and temporary data in Raid0).
Data libraries and backups, external drives only.
As my temporary work files/folders are fairly small (6-12GB), I can easily copy them to a different drive while I'm working when needed, without having mirroring slowing me down.
Needless to say, Time Machine is off at all times, only used manually in combination with SuperDuper , and the scratch and data Raid is not being indexed.
Imho, if you want super safe and fast, you have to set up some elaborate and costly external Raid.
Horst,I wouldn't mirror a stripe, but neither would I use it as storage or backup
I am talking about software RAID here because that is the only option the OP is willing to pursue at this point.
So RAID 1+0 (striping a mirror) is better than RAID 0 from a data security standpoint and better than RAID 1 from a performance standpoint. I would never use any setup, RAID or not, without some kind of backup which is why I suggested RAID 1+0 with Time Machine as ideal. That solution gives you improved performance, data security, higher availability in the event of disk problems, and access to files previously deleted files. All without costing an arm and three legs.
S-
I know what you mean, and agree ; my point is, you can't have it all when you are using internal drives only.
Speed or safety - pick one.
External HDDs are so cheap these days, it seems foolish to store non-essential files on internal drives - all in my humble opinion.
As for Time Machine : it's ok for system backups, and user folders, but that's about it. Even then, it's only good for basic restoring , on the very rare occasion one needs to go back in time to fix a messed up system.
It's a little bit like iLife - bloated, useless, low-quality, and you don't even have to train that monkey to use it
.
Horst,As for Time Machine : it's ok for system backups, and user folders, but that's about it. Even then, it's only good for basic restoring , on the very rare occasion one needs to go back in time to fix a messed up system.
It's a little bit like iLife - bloated, useless, low-quality, and you don't even have to train that monkey to use it
That's being a little hard on Time Machine, isn't it?
Having been bitten by backup software that didn't actually restore when I needed it, I ALWAYS test the restore function of backup software before I consider trusting it.
I installed Mac OS X 10.5 on a disk and enabled Time Machine to back it up. After it was done, I created some test files and let Time Machine back them up. I then let it install all the updates to take it to 10.5.6. Then I took the system disk out of my Mac Pro and stuck a new drive in its place. I booted the Mac OS X 10.5 installer disc and selected the "Restore System From Backup" option and pointed it to my Time Machine volume.
My system was restored with all test files in place. Everything worked as expected.
My point? Time Machine works for full system restores and for going back in time to find files you deleted. And it does all of this simply and without any training. Anyone can use Time Machine which is way more than half the battle. Based on what I have experienced in the Windows world, Time Machine is a phenomenal product and is all 95% of the users need.
S-
S-
Of course you need to make sure a backup software works before relying on it.
I don't think there is one I didn't try, and SuperDuper turned out to be perfect for me, being both easy and reliable .
Time Machine is not a backup solution in my book, just some tacky restore aid .
Being a default feature of Leopard, lacking proper customization tools, I'd actually call it bloatware .
I believe 95% of the users don't back up at all.
The remaining 4.5% using TM are posting here asking what 200TB drives to buy or how on earth to retrieve a file from their TM 'backup' .
Horst,
I can't agree with that on several levels.
While Time Machine does not offer much in the way of customization, it does do a very good job of backing up a system. As I am sure you are aware, it does this in two ways. The first, it allows you to restore files that you have deleted or modified by accident or on purpose. It does this amazingly well with an incredibly easy to use user interface. Second, it provides a restore mechanism that can be used to restore what you had in case of drive failure. This is a simple process using the install discs that come with the system.
Does it give the flexibility that True Image does on Windows or Amanda on Unix? No it does not. But that is not the intended market for the software. Time Machine is the first backup software that the masses are likely to use and get some benefit.
I have used True Image and Amanda for years. I'll be honest, I find Time Machine refreshing simple to use and it does what I need for backups on my system. I don't have to think about it. It just does its thing and simply works.
S-
n8236,
First of all, you can't do RAID 5 without a RAID card which the OP does not have. Second, RAID 5 is still not a substitute for having actual backups. So you need either Time Machine or Time Machine in conjunction with SuperDuper!.
S-
Using hardware RAID, yes.
But the OP gave the impression of using the Mac Pro's software RAID functionality, so no RAID 5 capability.
Its interesting that you have presented the solution without the requirements - what are your requirements; these appear to be governed around performance and speed within a tight budget. Is this a correct assumption?
Your best performance gain without going into software RAID 0 proprietary RAID cards or the expensive one from Apple would be a 300GB backplane version of the WD VelociRaptor drive for your apps and system. SSDs are still a bit expensive, small, new and vary greatly among vendors in performance and technology - there still isn't enough data for reliability.
WD just came out with a 2TB (Green) drive that would suit your requirement for Time Machine - does this really need super performance? For your remaining two bays you can go with RAID 0 for data (these could be smaller cheaper 500GB or 750GB drives too) and rely on your backup and Time Machine or just simply go with a WD Black or the Samsung you mention. In addition to the single data drive option you could put in another performance VelociRaptor for scratch if that is what you are after.
Your best performance gain without going into software RAID 0
proprietary RAID cards or the expensive one from Apple would be a 300GB backplane version of the WD VelociRaptor drive for your apps and system. SSDs are still a bit expensive, small, new and vary greatly among vendors in performance and technology - there still isn't enough data for reliability.WD just came out with a 2TB (Green) drive that would suit your requirement for Time Machine - does this really need super performance? For your remaining two bays you can go with RAID 0 for data (these could be smaller cheaper 500GB or 750GB drives too) and rely on your backup and Time Machine or just simply go with a WD Black or the Samsung you mention. In addition to the single data drive option you could put in another performance VelociRaptor for scratch if that is what you are after.
Somewhat agreeing with the above poster.
I would RAID 0 two Raptors, then have the Time Machine on a separate RAID 1 array of 1-2TB drives.
I would RAID 0 two Raptors, then have the Time Machine on a separate RAID 1 array of 1-2TB drives.
My requirements are storage, then speed, then reliability.
As I mentioned, I have most of my important files backed up to one or more of several places (online, CDs/DVDs, external HD, etc.). I already own four 1-terabyte hard drives (all 7200 RPM), and I don't want to buy anything else.
I've made a decision, though I'm not done executing it, so I suppose I could still modify my plan:
- I made a 128 GIG partition on one of the drives (#3) and installed a fresh system on it.
- I took the remainder of that drive and striped it with a full-capacity drive (#4) and will use that volume for Time Machine.
- Once I've backed up all my data on my 2 existing drives, I will wipe those, partition a 32 GIG section on each, and stripe those partitions together for a 64 GIG "scratch" partition
- I'll then partition the remainder of those drives together for my main "data" volume.
That leaves me with 4 volumes:
- "scratch" (striped RAID across drives 1 & 2)
- "data" (striped RAID using the remainder of drives 1 & 2)
- "system (single volume on drive 3)
- "Time Machine" (striped RAID across drives 3 & 4)
If drives 1 and/or 2 fails -- I can replace the drive(s), re-stripe and then restore from TM
If drive 3 fails, I'll have to replace it, install a new system, and rebuild TM
If drive 4 fails, I can replace it re-stripe it with the big partition on #3 and re-build TM.
If drive 1 or 2 fails AND drive 3 or 4 fails, well -- that would suck, but like I said, I've got most of my stuff backed up elsewhere anyway.
If 3 or more drives fail, it's likely because the US has sustained an EMP from a nuke detonating in the upper atmosphere, and at that point, my iTunes library will be fairly low on my list of concerns.
-J
As I mentioned, I have most of my important files backed up to one or more of several places (online, CDs/DVDs, external HD, etc.). I already own four 1-terabyte hard drives (all 7200 RPM), and I don't want to buy anything else.
I've made a decision, though I'm not done executing it, so I suppose I could still modify my plan:
- I made a 128 GIG partition on one of the drives (#3) and installed a fresh system on it.
- I took the remainder of that drive and striped it with a full-capacity drive (#4) and will use that volume for Time Machine.
- Once I've backed up all my data on my 2 existing drives, I will wipe those, partition a 32 GIG section on each, and stripe those partitions together for a 64 GIG "scratch" partition
- I'll then partition the remainder of those drives together for my main "data" volume.
That leaves me with 4 volumes:
- "scratch" (striped RAID across drives 1 & 2)
- "data" (striped RAID using the remainder of drives 1 & 2)
- "system (single volume on drive 3)
- "Time Machine" (striped RAID across drives 3 & 4)
If drives 1 and/or 2 fails -- I can replace the drive(s), re-stripe and then restore from TM
If drive 3 fails, I'll have to replace it, install a new system, and rebuild TM
If drive 4 fails, I can replace it re-stripe it with the big partition on #3 and re-build TM.
If drive 1 or 2 fails AND drive 3 or 4 fails, well -- that would suck, but like I said, I've got most of my stuff backed up elsewhere anyway.
If 3 or more drives fail, it's likely because the US has sustained an EMP from a nuke detonating in the upper atmosphere, and at that point, my iTunes library will be fairly low on my list of concerns.
-J
I take it you like living dangerously when it comes to your data.
I see a problem with drives 3 & 4. The partitions must be the same size, if not using the entire drive when creating a strip. To balance it, what ever the size of the OS partition, you'd have to do the same with drive 4. Then stripe the two remaining pieces of both drives. Otherwise, you get wasted space. (It's always based on the smallest component, whether it be a partition, or the entire drive).
You'd be better off rethinking this I think. Separate as much as you can. For example, your setup of drives 1 and 2, put high usage on it 2x, as it's handling data and scratch files.
I think you'd be safer to just split it into (non RAID):
drive 1 = OS
drive 2 = Scratch
drive 3 = Data
drive 4 = Time Machine
The load would be split among completely separate drives, so you would get a higher throughput.
Beyond that, you get into RAID.
Consumer drives aren't really up to the task, as their unrecoverable bit error is a little low for such usage. If you do decide to go this route, and use the existing equipment, you might want to re-examine the RAID 1+0 suggestion. The MP is capable of this via software RAID. Better than RAID 0 any day, as you have some redundancy, and still get a speed boost. Anything else would require a RAID card, bare minimum, keep spares on hand, and switch to enterprise drives. It might seem obsessive, and over blown, but it's the result of experience.
I appreciate a little more discussion on plausible internal RAID solutions for the MP. I started a similar thread recently and am still trying to learn as much as possible while I wait for Gainestown.
I am, however, going to latch onto something here that may be a bit peripheral- ZFS. A couple of posters have mentioned it in relation to Snow Leopard, but this is the first I've heard of it in probably a year or more. Last I heard, there was no reason to believe it had become bootable with OSX.
Of course, in the back of my mind, I've been wondering if they had made it work and would introduce it in SL; but has anybody seen evidence of this, or is this mostly educated speculation? I'd love to believe that we might have ZFS-based Snow Leopard running on Gainestown chips this year, including self-healing expandable storage pools and efficient system snapshots.
The last I saw, ZFS is slated for the Server edition of Snow Leopard, not the Client edition. It would be placed into the client edition at a later date, either as an update, or not until 10.7. (Personally, I lean towards the latter, as updates gives them time to work out whatever issues it might have).
The last I saw, ZFS is slated for the Server edition of Snow Leopard, not the Client edition. It would be placed into the client edition at a later date, either as an update, or not until 10.7. (Personally, I lean towards the latter, as updates gives them time to work out whatever issues it might have).
I'd actually say as a client download.
I wouldn't be the least bit surprised to see a stable version of ZFS available on macosforge (edit
when Snow Kitteh is launched.Not advertised by Apple, of course, but there for those of us who know what we want and will use and recommend FAT32 if we can't get it!
Mmm... That would be nice!I'd actually say as a client download.
I wouldn't be the least bit surprised to see a stable version of ZFS available on macosforge (edit
Not advertised by Apple, of course, but there for those of us who know what we want and will use and recommend FAT32 if we can't get it!