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View Full Version : Mac Mini Server - Mirrored RAID vs. Time Machine




justinm
Mar 14, 2010, 06:42 PM
Not sure if this should go into the Mac mini forums..... but I just purchased a Mac mini server. For backups, what do you think is better? A mirrored RAID on the 2nd 500gig drive or back up with Time Machine? I was thinking RAID because if a drive dies, I can easily swap it out and make the copy the primary drive. The server will be mostly a Email/Backup web server.



chown33
Mar 14, 2010, 07:04 PM
No comparison.

RAID is redundancy to protect your current data. It's not a backup.

Time Machine is redundancy to protect your past data.

For maximum protection, RAID your current data and RAID the Time Machine disk.

justinm
Mar 14, 2010, 07:14 PM
OK, thanks!

stukdog
Mar 16, 2010, 02:32 PM
Be advised that Time Machine won't backup your data, just your settings. So, a restore will get you up and going again, but you'd have to restore your mail data, etc by hand.

chown33 makes some good points. So often RAID is mistaken as a backup.

From my experience, I would use Super Duper to clone from the primary drive to the secondary drive on a regular schedule. And if you won't be using the full 500GB, you can partition the second drive and do one weekly partition and one daily partition. That give you a little access to past data should you miss corruption before it is cloned over.

Anyway, hope that helps

talmy
Mar 16, 2010, 02:40 PM
I'm going to chime in here and say "Neither." You need to consider what you are protecting against. RAID 1 protects you against failure of a drive and gives you nearly zero downtime, at least in systems which have hot swappable drives (the Mini doesn't). You could still be down for several days if you have to rely on Apple to swap drives. And system failures can wipe out both drives, and you would lose everything.

TimeMachine I consider to be an easy to use versioning tool, so you can go back and retrieve files that were badly edited or deleted. It has problems as a backup -- inability to easily handle alternate drives and offsite backup. Restore is very slow. Also they seem to corrupt way too often to rely upon as a general backup.

Neither of these solutions protects you from theft or natural disasters. For that your best bet is an image backup (SuperDuper! or Carbon Copy Cloner are the best know programs for this). Alternate between two drives, and keep them off-site. Some people attach a drive and have scheduled backups on a daily or more frequent basis, and swap the external drives every few days or weekly. It all depends on how current you want protection. The backups can be done incrementally and are fairly fast.

In my case I'm not using it for mail and have SuperDuper! scheduled to do a back up every night. I have two drives so I can switch them every week. I've got the two drives in RAID0 for performance, satisfied that even if that fails, losing the current day would be acceptable. I sleep well enough with that. On the systems with mail, I use Time Machine combined with weekly SuperDuper! image backups.

crazzyeddie
Mar 16, 2010, 07:55 PM
Be advised that Time Machine won't backup your data, just your settings. So, a restore will get you up and going again, but you'd have to restore your mail data, etc by hand. ...

Uh... thats completely untrue. Time Machine backs up almost all data and settings, but not your system files.

However, for a server, I would still recommend Carbon Copy Cloner or the equivalent...

stukdog
Mar 17, 2010, 11:57 AM
Uh... thats completely untrue. Time Machine backs up almost all data and settings, but not your system files.


It does a good amount, but not complete. From the Apple Documentation for setting up Snow Leopard Server (http://images.apple.com/server/macosx/docs/Advanced_Server_Admin_v10.6.pdf) (PDF):


"At its core, Time Machine is a file-level backup solution that runs at regular intervals and archives file changes from the initial file set. Time Machine makes use of UNIX file linking to efficiently store backup intervals as separate browsable file systems, but uses no compression.
Time Machine is a limited tool for data backup and restoration of Mac OS X Server v10.6. It can back up some server configuration settings and the service state. Time Machine does not back up service data.

For example, Time Machine doesn’t back up user and group directory records, email, DNS records, Address Book shared groups, iCal Server calendars, and so forth. It only saves the settings made in Server Preferences and Server Admin, and whether a service is on or off. "

Deanster
Mar 22, 2010, 12:24 AM
Good advice above.

From a server perspective, Time Machine is ONLY good for helping with the 'oops, I deleted a file I didn't intend to' issue. It is NOT NOT NOT a full-spectrum backup tool, and you'd be in for a HORRIBLE surprise if you used it that way.

IMHO, if you're going to the trouble of running a server, you have needs sufficient to warrant setting up a multi-layered backup program.

My former Xserve setup used the following. Two internal drives configured into a Raid 1 mirror, with the idea that a dead drive would result in zero downtime (which wasn't quite true - when one drive died, I needed to shut down the computer, remove the drive, and start back up - 5 mins downtime). One larger internal drive configured into three partitions, each large enough to hold the main drive's contents. One was a scratch partition, and the other two were destinations for SuperDuper backups. One ran automatically at 7pm each day, to capture the day's work. The other ran every week on Friday at 9pm, so I'd have a several-day old backup most of the time. Finally, I had an external Firewire/USB drive, and ran a SuperDuper backup each day right after lunch. This drive went home with me at the end of the day to provide an off-site backup with day-old contents.

This gave me a pretty good set of backups - protection against drive failures, a hot backup with yesterday's end of day data, and a mostly-offsite backup with yesterday's mid-day data.

But... even with that level of backup, there's several gaps. My off-site backup was onsite all day, making it vulnerable to theft, flood, fire, etc., along with the primary. I didn't have a backup more than a week old anywhere, and i wasn't using Time Machine for iterated backup of files.

A reasonably complete backup plan would have added two more external drives for the off-site cycle, so I was alternating days with two drives, leaving one offsite at all times, and the other going in only every other or every third week, so I had an older copy offsite as well, as well as giving Time Machine space on the internal backup drive, so I had onboard file recovery.

Now, the sane person says, 'what a giant pain! do I really need a mirrored pair, a really big onboard drive with three or four partitions, and THREE external drives to cover backup duties?'

What's your data worth? What happens if you lose it? Can I be down for an hour? a day? a week? Can I afford to lose a day's data? how 'bout a week? For some businesses/organizations, it'd be trivial. For others, being down for a couple days and losing a week's transactions would be the end of the business.

What happens if there's a disaster, and the fire sprinkler goes off right over your server? That might well kill your mirror, onboard drive, and external daily backup drive all at once. Earthquake/Flood/Storm? Break in at night and all the hardware is stolen?

Lots of decisions to make... good luck!

ChrisA
Mar 22, 2010, 11:55 AM
Be advised that Time Machine won't backup your data, just your settings. So, a restore will get you up and going again, but you'd have to restore your mail data, etc by hand.

The above a not true. Time Machine will backup every file on the disk.

Well, OK if you like you can tell Time Machine tonot backup some file. But you have to take action to do this. By default it backs up everything.

One more exception. Tine Machine does not backup the time machine disk. It would be kind of pointless.

So I'll say the TM baks up every file that is not on the Tine Machine disk unless you specifically tell it not to.

Tinme Machine is a very good "first step" in setting up a backup system. You shoud buy an external disk that is at least 1.5 times larger (2x is better) than all the disks you need to back up . Yes the TM disk shoud be the largest disk you have. Let TM run automatically.

Then IN ADDITION you need more. You need a copy of your data in some off-site location in at least another building. The best plan is to rotate a pair of disks to the off site location

What's your data worth? What happens if you lose it? Can I be down for an hour? a day? a week? Can I afford to lose a day's data? how 'bout a week? For some businesses/organizations, it'd be trivial. For others, being down for a couple days and losing a week's transactions would be the end of the business.

The above really does sum it all up. If the data is just some video ripped off DVDs then it is not big deal if it is all lost. The data would be easy to replace. But what if you are a profesional photographer or a software developer. then the data can be worth hundreds of thousands of dollars and it would be worth spending $1K to keep it backed up.

I while back I started a project to scan some old family photos. Some were 100 years old. It got me thinking that in 100 years there will be very, very few 100 year old photos. People keep their phots on disk now days and few few people have a backup system that will keep data for 100 years.

hakuryuu
Mar 22, 2010, 04:37 PM
Be advised that Time Machine won't backup your data, just your settings. So, a restore will get you up and going again, but you'd have to restore your mail data, etc by hand.


Time Machine backs up everything.

iltmimi
Mar 22, 2010, 05:40 PM
Er,

I have personally recovered from a total hard drive loss in my MacBook Pro using Time Machine.

1) Replace broken drive with new one
2) Insert Snow Leopard installation CD and boot
3) Choose Time Machine backup to restore from.

Attachment related...this is what you get in step 3. I was so impressed I had to take a picture :)

belvdr
Mar 22, 2010, 06:29 PM
The above a not true. Time Machine will backup every file on the disk.

Well, OK if you like you can tell Time Machine tonot backup some file. But you have to take action to do this. By default it backs up everything.

Not on OS X Server.

Time Machine backs up everything.

No again.

Er,

I have personally recovered from a total hard drive loss in my MacBook Pro using Time Machine.

1) Replace broken drive with new one
2) Insert Snow Leopard installation CD and boot
3) Choose Time Machine backup to restore from.

Attachment related...this is what you get in step 3. I was so impressed I had to take a picture :)

That's not OS X Server.

I believed it would backup everything too, until I read the document stukdog linked to. My guess is it backs up the data for whatever user you use to setup the TM backup, but it won't backup any of the other service data.

talmy
Mar 23, 2010, 04:48 PM
Even more disturbing that the TimeMachine does/doesn't backup up everything subtopic is that apparently SuperDuper!/CCC won't do it either. The problem is that Snow Leopard Server maintains configuration in databases that cannot be successfully backed up while the services are running.

This means that you either have to shutdown all the services, do the back-up and then turn on the services, or you need another approach. Obviously shutdown won't work for TimeMachine, and with SD!/CCC it would mean that the server would be down during the backup, which might be OK if scheduled in the dead of night and the machine doesn't require 24/7 access.

For an alternative, a sample script is provided on the CCC site: http://bombich.com/software/docs/CCCHelp/CCCHelp.html?page=advsettings (http://foo) Recovery will still be a manual process, and you can't simply boot from the clone.

No matter how you look at it, it's going to be a PITA. I couldn't find this subject addressed in any of Apple's documentation.

Alrescha
Mar 23, 2010, 05:49 PM
To further confuse matters, if you look at what happens when a backup is run on OS X Server, you'll see that a number of extra backup scripts/programs are run (which back up the LDAP database, for instance) but I have yet to see any documentation from Apple which mentions how to make use of the resulting backups.

A.

talmy
Mar 23, 2010, 10:08 PM
If you use Server Admin and use the two File->Export choices, they can be restore via File->Import (I hope!). The Open Directory database can be backed up using the Archive tab, and restored from there as well. Or the MySQL dump program can be used to create a file that can recreate the database.

But I'd sure like to see some definitive documentation about all of this.

corbywan
Mar 24, 2010, 10:53 AM
Man! Here I was getting all set to setup a CCC and TM approach, and I learn that it won't even really work? Is there any definitive documentation on the issue of backing up Mac OS Server?

I'm running a web/email/file/podcast server with a relatively light load. It can easily be taken offline for backup in the middle of the night. I'm guess some kind of scripting could accomplish all of this, but is there an out-of-the-box something that will do this for me?

talmy
Mar 24, 2010, 02:29 PM
Man! Here I was getting all set to setup a CCC and TM approach, and I learn that it won't even really work? Is there any definitive documentation on the issue of backing up Mac OS Server?

I've done lots of searching, including Apple's SLS docs, and came up empty handed. And although I know how to shut off and turn back on services in Linux from the command line, I don't know how for SLS. Indeed, in my application, that plus SuperDuper! (or CCC) would be the easiest solution since I don't need 24/7.

Tonight I'm going to see if I can successfully run from a SuperDuper! cloned drive with exported configuration and Open Directory database restored from copies saved from within the admin program. Since I don't intend to be changing configuration that often, if this works I can just go with that.

I've seen some references to "you have to take special steps" to have a good backup, but it appears that the Loyal Fraternity of IT Professionals are not about to part with their secret knowledge (at least not unless you hire one as a consultant).

The web site for Carbon Copy Cloner shows a script to do a backup, but not a restore. An email to SuperDuper! support got a quick reply that they support pre-execution and post-execution scripts to handle this situation, but didn't suggest or supply any scripts. And, of course, TimeMachine will be of no help as you can't open Server Admin, start time machine, and go back to past settings.

carlclarke
Mar 24, 2010, 03:56 PM
As you can see from all of the answers/suggestions above - there are many ways to go about achieving a backup. I think that you should revisit your requirements to see what you actually need to achieve.

However from my experience:

CarbonCopyCloner will give you an alternative bootable disk, I have used it to transfer a whole working system from one disk to another when upgrading the disk drive in a Mac Mini. No special magic was required for me to do this, apart from the putty knife to open the Mac Mini :)

I have a Mac Mini Server - the one that Apple sells with 2 x 500GB configured for mirroring. I suspect that the space would soon be used up with all of the hourly/daily/weekly/etc. backup data and certainly the time taken to transfer many Gigabytes of data is considerable even on a Gigabit ethernet network. However there is something very convenient about being able to just get a backup going across AirPort when you are within range of your base wireless network, in the same way that it works with Time Capsule. If I was going to use my Mac Mini Server as you describe I would not use the internal mirrored drives for backup storage for the good reasons stated in previous posts; you may not be able to access your backups easily or quickly in the event of a failure. Consider adding an external RAID solution to the server like the Drobo (or similar, or RAID NAS) so that you can get access to it if your server needs repair.

With the appropriate RAID configuration you are trying to protect against a hardware failure. With Time Machine you are storing versions of your data and that gives you two main benefits (1) Obviously you have a restorable backup copy that can be constructed from the versions (2) Your subsequent backups are quite fast because you are just storing the differences in most cases. So if speed of backup is important to you then a Time Machine like differential backup is good. If you need to access some historical data, say the version of a document three days ago, then again Time Machine is good. If however you just need the security of having a system up and running as fast as possible and you don't care if the 'backup' takes hours every day then consider taking an image of your system using CCC/SuperDuper. Also - there is nothing worse than designing your solution to find that when that day comes and you have a failure - your solution does not work! You will have to devise a (very safe) way to test it out.

Before you do anything though - establish your exact requirement and see how it fits in the environment that you work within.

Good luck

Abacab
Mar 24, 2010, 06:52 PM
Don't know what you folks are smoking, but here is my setup:
Xservevia Fiber to a Promise Vtrak Raid (data stored on raid)
Everything backed up via Time machine via ISCI to a 26 TB Nas.
My raid failed and I restored 8 TB of data in less than 6 hours.
Am I missing something?

talmy
Mar 24, 2010, 07:40 PM
Not smoking anything, but the OP asked what's better for backing up a Mini with Snow Leopard Server -- RAID1 or Time Machine? Then others pointed out that RAID wasn't a backup, and that there are also cloning programs like SuperDuper! and CCC. The problem is that the Open Directory database and possibly others won't be successfully backed up by either of these means, so that you might be able to boot from a clone, or restore from Time Machine you would not have your server functionality restored.

Just restoring data files on the server, or restoring anything to NAS, SAN, or other storage device is not the problem or relevant. We all know that can be done.

talmy
Mar 24, 2010, 10:02 PM
I did the "acid test". I took a SuperDuper! clone of my Mac Mini Server and booted from it. It took several minutes for everything to come up but the Open Directory listings and all the shares were in place! It looks like, at least for me and my current set of services I'm using, the SuperDuper! backup is adequate. Of course you results may differ. Conventional wisdom is to always check you backups by attempting a restore. It certainly applies here as well to check that you bootable clone drive is functional.

I'm still going to export the settings and the Open Directory database when I make changes, just in case.

talmy
Apr 2, 2010, 09:12 AM
I've got to follow up to this with "bad news".

It looks like, at least for me and my current set of services I'm using, the SuperDuper! backup is adequate.

I'm still going to export the settings and the Open Directory database when I make changes, just in case.

Turns out that you do need to export/archive the Open Directory database when you change it. Yesterday I had the misfortune of having to restore my server from the latest backup (which, BTW, only took 5 minutes!). Open Directory was toast, with several passwords, including that of the Directory Administrator, garbled. A restore of the archived open directory fixed it.

So, to repeat, TimeMachine/SuperDuper!/CarbonCopyCloner are NOT SUFFICIENT in themselves to back up Snow Leopard Server! You need to at least archive the Open Directory as well. CarbonCopyCloner website has a script that will do this. I'm using SuperDuper! but will make use of that script in my nightly SuperDuper! backups.

Alrescha
Apr 2, 2010, 10:04 AM
You need to at least archive the Open Directory as well. CarbonCopyCloner website has a script that will do this. I'm using SuperDuper! but will make use of that script in my nightly SuperDuper! backups.


Time Machine runs a pre-backup process (ServerBackup) on Snow Leopard Server which backs up lots of server stuff, including Open Directory. You'll find the results of that process in:

/Volumes/<time machine>/Backups.backupdb/<hostname>/Latest/Server HD/.ServerBackups

There is a man page for ServerBackup (case sensitive).

A.

talmy
Apr 2, 2010, 04:14 PM
ServerBackup is great news! I can run it as part of the SuperDuper! backup script. That beats using the fairly length bash script found on the CCC site to do this.

michaelbyfield
Jun 11, 2010, 02:15 AM
Hi There

Im new to this so I hope that I am posting in the right place.

I have a Mac Mini Server running time machine which is "backing up" the second HD in the Server.

It worked fine for a week or so, but now when I try to 'enter time machine' it doesn't work properly and instead all it does is open the above window twice.

When I close the first window the time machine bar shows but not properly, and doesnt work, and when you close the second window it is all back to normal.

Sorry, it is backing up to a mirrored software raid which is accessed through USB

talmy
Jun 11, 2010, 11:17 AM
As many people have said in this thread, don't back up you server with TimeMachine.

romeyn
Jul 14, 2010, 12:56 PM
Time Machine runs a pre-backup process (ServerBackup) on Snow Leopard Server which backs up lots of server stuff, including Open Directory. You'll find the results of that process in:

/Volumes/<time machine>/Backups.backupdb/<hostname>/Latest/Server HD/.ServerBackups

There is a man page for ServerBackup (case sensitive).

A.

I found this thread because I just accidentally deleted a Computer Group in WGM and figured restoring OD from Time Machine would be easier than re-creating that group from scratch.

But how?

I found the OD backup sparseimage in the folder mentioned above and copied it out to the desktop. I then used Server Manager--Open Directory-->Archive to back up OD as-is (just in case) and then chose to restore from the archive I had dragged from the desktop. I was given the option to MERGE that data into the OD current state, which I did.

My group is back as if nothing had happened. So I'm not sure what all the anti-Time Machine sentiment is about, but it seems to do exactly what I expected it to: save my butt when I've been stupid.

talmy
Jul 14, 2010, 02:58 PM
So I'm not sure what all the anti-Time Machine sentiment is about, but it seems to do exactly what I expected it to: save my butt when I've been stupid.

TimeMachine won't back up everything, and the documentation isn't clear exactly what is and isn't backed up. And you can't boot from a time machine backup. Having an image backup gets you up and running faster when everything has gone belly up. My OD changes very infrequently so I just do a manual backup. There have been times when I have needed to boot from the clone drive and had to restore OD from the backup, so I know it all works.

michaelbyfield
Jul 15, 2010, 01:47 AM
Hi thanks for your comments, I'm not sure what all the negative press is about either.

I have 1 MacMini server serving eight windows laptops and two mac book pro's.

A software RAID system backing up the server. The server is also backed up to my Macbook Pro via Chronosync, and then both the MacBooks are backed up to a 1TB time machine.

The only thing that isn't quite right is the Time machine front end on the server, apart from that, all the files are backed up right up to date.. Seems like a minor niggle, and I haven't quite got something right rather than a serious problem?

talmy
Jul 15, 2010, 10:41 AM
The only thing that isn't quite right is the Time machine front end on the server, apart from that, all the files are backed up right up to date.. Seems like a minor niggle, and I haven't quite got something right rather than a serious problem?

You will never know how quite right things are until you attempt to do a restore. Some things to attempt:

1. Ability to completely restore system as well as boot from an external backup.

2. Ability to restore Open Directory

3. Ability to restore other databases such as address book and calendar.

4. Ability to restore files on shares

5. Ability to restore files in user folders

6. Ability to restore web pages

If TimeMachine is working strangely, how do you know you can do a restore?