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theSchtickler
May 1, 2008, 01:59 AM
Ok,

As much as this could be a appauling movie, it's actually a problem I face....

Got a network RAID drive (running in RAID 0) and wish to use it as a time machine back up for myself and two others.

I have it on the network as a smb drive, i can log onto it, and copy files to it.

After some stuffing around, I got it to show up in TimeMachine as a drive I could use to back up (there's a line you type into Terminal). Problem is, when TM goes to do the back up, it starts, then after a minute or so bugs out and says that it can't use the drive!

I have the drive RAID 0 formatted with a EXT2 setting, if that means anything to anyone?

Any suggestions?



bdorpetzl
May 1, 2008, 09:52 AM
Ok,

As much as this could be a appauling movie, it's actually a problem I face....

Got a network RAID drive (running in RAID 0) and wish to use it as a time machine back up for myself and two others.

I have it on the network as a smb drive, i can log onto it, and copy files to it.

After some stuffing around, I got it to show up in TimeMachine as a drive I could use to back up (there's a line you type into Terminal). Problem is, when TM goes to do the back up, it starts, then after a minute or so bugs out and says that it can't use the drive!

I have the drive RAID 0 formatted with a EXT2 setting, if that means anything to anyone?

Any suggestions?

I don't think that this is an issue with your RAID, rather it is the way TimeMachine works. I found this page (http://www.macosxhints.com/article.php?story=20080420211034137) to be helpful when trying to use my NAS as a time machine. I haven't completed a backup, but I a fairly certain it works because I was able to get the back up started, but it would have taken nearly 6 hours (I was doing it wirelessly).

Hope this helps.

mac666er
May 1, 2008, 06:57 PM
I have the drive RAID 0 formatted with a EXT2 setting, if that means anything to anyone?

Any suggestions?

The EXT2 is a file system used mainly for LINUX. You can use it from OS X, but macs currently use HFS+ and maybe someone can clarify this further but to use Time Machine I believe not only that you had to use HFS+ as the format of the volume but also enable journaling on it.

Journaling very broadly speaking is a log or journal of the file activity on the volume, hence time machine can reference this info to "retrieve" previous versions of a file.

I thought that in order to enable time machine you had to use an HFS+ with journaling selected when formatting the drive through disk utility.

On an additional note, I have read people having problems with RAIDs and case-sensitive journaling (they claim performance issues). But I haven't tried this at all. (When you format a volume through disk utility, you can choose case sensitive journaling or regular journaling).

Good luck and let us know how your Time Machine experience goes!

M.

theSchtickler
May 1, 2008, 10:38 PM
OK,

So after going to the page that bdorpetzl suggested, we are off and racing. (Thanks :) )

Now.... I'm backing up 190GB for the first computer, its going ok but it seems sloooooooow. It's taken like 2hrs for 30GB, is this just time machine? The network is all 1000T, and I can copy a 1GB file from one mac to the other in 30secs?

Do you think this could be because it is across SMB? There is another RAID I'm considering swapping to that supports AFP, do you think it would be worth it?

127079
May 2, 2008, 03:47 AM
this might help, I havent used it myself, but could be worth a try

http://www.xiotios.com/itimemachine.html

Ren

127079
May 2, 2008, 03:56 AM
this might help, I havent used it myself, but could be worth a try

http://www.xiotios.com/itimemachine.html

Ren

RedTomato
May 2, 2008, 04:44 AM
To be honest, backups are so important that I would not consider running any kind of unsupported hack to TM.

With the Terminal hack, it may work fine, but will you still be able to restore in a month's time? Will it cope with your laptops popping and out of the network? With wifi network links dropping at the most sensitive times?

You risk silent corruption of the database bundles, and not finding out until months later. Given that, I say the risk of false security, and the possible effect, is too high.

I run our network TM on a firewire external attached to an old powerbook, which hosts all our TM backups, and does a few other server duties.

There's three of you, surely you can find the money between you to get an old iBook or MacMini to use as a TM host?

PS: I did the first backups with our macbooks running overnight, either plugged directly into the network hub or just with wifi, depending on the size of the backup. Also some consideration of which folders to exclude from TM helps to reduce the size of the hourly backups.

mac666er
May 2, 2008, 01:44 PM
You risk silent corruption of the database bundles, and not finding out until months later. Given that, I say the risk of false security, and the possible effect, is too high.



I just realized I didn't mention this in my first reply, and this is why I mentioned the HFS+ formatting and journaling: RedTomato is spot on, you are hacking a backup functionality and adding to what he said: you are running a RAID 0 volume, which is just data stripped over two drives, which means that if one goes down you lose ALL your data. (and believe me the hard drive is the most likely part of a computer to go down in flames... it DOES happen)

I don't think I have seen people backing up to a RAID 0 volume precisely because of this, you are in fact augmenting the probability of losing your data because: there is a de-facto failure probability of failure on each drive, but you are compounding it by combining the two of them since any failure translates to a total data loss for you. Even worse, if the drives used come from the same manufacturer it means that once a drive fails it is very likely the other one will fail as well (because they came from the same factory and process, which means they probably share the same faults). So that is why RAID 1 (mirroring the information from 1 drive into another) uses (at least preferably) different drives from different brands.

When you experience a data loss you are going to wish you had NOT used a RAID 0 volume to back up your stuff. If you can, at the very least reformat the drives to not be in RAID 0, you will lose performance, but this doesn't matter for a backup since it happens in the background anyway and besides, whatever speed performance you get from the RAID is neglected by the network you use, and how you connect the drive. This is specially true if you use any type of wifi (which is orders of magnitude slower than any RAID 0 read/write speed). If you connect it via firewire or worse USB, then all the speed in your 1000T network is not going to be used as all that data is waiting to go through firewire or USB speeds.

Ideally you should use RAID 1 for this, then when one drive fails you can just switch it off, throw the old drive away and put another drive of the same capacity in and you are back in business, as good as new.

Good luck!

M.

RedTomato
May 2, 2008, 07:06 PM
Ideally you should use RAID 1 for this, then when one drive fails you can just switch it off, throw the old drive away and put another drive of the same capacity in and you are back in business, as good as new.

Thanks for the backup Mac666. I just want to add, that with a home RAID 1 array, if it's more than a year old, chances are that the HD model is no longer available. I've seen RAID guides that state it's not enough to just have the same size, you also need the same manufacturer, same disk model, and sometimes even, where possible, the same stepping.

So if a disk in a RAID1 array fails, the best option is to buy *two* new disks and copy the data over to a different external drive before replacing both disks in the RAID1 array.

gnasher729
May 3, 2008, 09:49 AM
That Terminal hack doesn't make Time Machine work. Time Machine _knows_ that it can't use your setup, and the hack makes it use it even though Time Machine knows better. Time Machine requires a feature that isn't implemented on any network drive (HFS+ with hard links for directories), and until that is implemented in the software of your network drive, Time Machine just cannot work.

The only people who should use this hack are people developing software for network storage devices who want to make their devices Time Machine compatible and need to test it.

theSchtickler
May 5, 2008, 01:38 AM
That Terminal hack doesn't make Time Machine work. Time Machine _knows_ that it can't use your setup, and the hack makes it use it even though Time Machine knows better. Time Machine requires a feature that isn't implemented on any network drive (HFS+ with hard links for directories), and until that is implemented in the software of your network drive, Time Machine just cannot work.

The only people who should use this hack are people developing software for network storage devices who want to make their devices Time Machine compatible and need to test it.

But isnt the HFS+ formatting thign fixed when you create a sparsebundle? I mean, thats the whole point of making a sparesbundle yeah?

Anyway, got rid of that network drive, and onto a new one.... the Lacie 2Big ethernet drive.

It is def going faster. My test file took 90 secs to copy to that last drive over SMB, this time it does it in 60 secs. So a good improvement, it must be due to the fact the drive supports AFP.

I still wonder though, why can I copy that same file to another mac in 30 secs, but it takes twice as long the the NAS? I know the NAS is in ext3 format but twice as long?

Krevnik
May 5, 2008, 11:42 AM
But isnt the HFS+ formatting thign fixed when you create a sparsebundle? I mean, thats the whole point of making a sparesbundle yeah?

I filed bugs on Apple because the sparsebundle didn't behave as expected on SMB sharepoints. ;)

Just because the sparsebundle was intended to get around a scenario, doesn't mean it works like one expects. Apple for the most part seemed to disable Time Machine than fix the underlying bugs that were preventing it from working correctly.


Anyway, got rid of that network drive, and onto a new one.... the Lacie 2Big ethernet drive.

It is def going faster. My test file took 90 secs to copy to that last drive over SMB, this time it does it in 60 secs. So a good improvement, it must be due to the fact the drive supports AFP.

I still wonder though, why can I copy that same file to another mac in 30 secs, but it takes twice as long the the NAS? I know the NAS is in ext3 format but twice as long?

The NAS is a ReadyNAS I presume? Maybe an NV or NV+? The only beef I had with the ReadyNAS is that because of the weak processor, it was very limited on the IO it could handle compared to some more expensive RAID boxes.