Question about JBOD

[Cave Man]

I have two 750 gb drives that I want to put together as a JBOD as a Time Machine volume. Is there an advantage to having the drives in an external enclosure, such as this one, vs. inside my tower? If inside the tower, I'm concerned that if there's a failure of my boot drive that I would lose the JBOD TM backup.

TIA.

 

[sickmacdoc]

Well if you really, really want to use JBOD for your backup I would say that the external case is a better choice in that the JBOD is handled by the in-case hardware controller rather than being a software controlled Concatenated set (as Disk Utility calls it) with internal drives.

I would think that you really should give some consideration to trusting a JBOD as a backup destination honestly. Since you are now using two drives (in your case) in the name of increasing space you have doubled the likelihood of a drive failing since there are now two potential failure points- and if one drive in a JBOD dies, the JBOD itself dies with no ability to just replace the failed drive and continue on. Just take that into consideration before you make a decision!

 

[Cave Man]

Well if you really, really want to use JBOD for your backup I would say that the external case is a better choice in that the JBOD is handled by the in-case hardware controller rather than being a software controlled Concatenated set (as Disk Utility calls it) with internal drives.

I suspected as much, but did not know for sure. Thanks for that info.

I would think that you really should give some consideration to trusting a JBOD as a backup destination honestly. Since you are now using two drives (in your case) in the name of increasing space you have doubled the likelihood of a drive failing since there are now two potential failure points- and if one drive in a JBOD dies, the JBOD itself dies with no ability to just replace the failed drive and continue on. Just take that into consideration before you make a decision!

The problem I'm having is that my new boot drive is 1TB and my TM volume needs to be larger than that (practically-speaking), which leaves me with the 1.5TB Seagate that has real issues. I have two of them for my media and one had to be replaced two weeks after I bought it. So, which is more risky - two 750GB drives or one Seagate 1.5TB drive? I'm not entirely happy with either choice.

 

[sickmacdoc]

I suspected as much, but did not know for sure. Thanks for that info.
The problem I'm having is that my new boot drive is 1TB and my TM volume needs to be larger than that (practically-speaking), which leaves me with the 1.5TB Seagate that has real issues. I have two of them for my media and one had to be replaced two weeks after I bought it. So, which is more risky - two 750GB drives or one Seagate 1.5TB drive? I'm not entirely happy with either choice.

Yep, that does put a spin on things. First of all, I personally would not consider a 1.5Tb drive from Seagate at this point in time with the notable issues that have been posted here and elsewhere. There is no doubt that the issues will get ironed out eventually and they will be great drives to have but for now not so much!

So then that leaves a couple of other thoughts to avoid that and the JBOD scheme as well. Have you considered partitioning your boot drive into perhaps two partitions of 500Gb each(or any combo of partitions to add up to your 1Tb drive)? In that fashion, you could have TM back up the boot partition to one of the 750Gb drives (and it would last quite a while since I doubt you have anywhere near 500Gb on your boot (right now anyways), and use Carbon Copy Cloner, SuperDuper, Chronosync, etc. to back up the second 500Gb partition to the other 750Gb drive.

Just a thought for a good workaround for your existing drives without being forced into a JBOD configuration anyway. At some later time when the 1.5Tb drives are working right you could get one to expand your backup capacity (and perhaps make your boot drive back to 1Tb) and do some other reconfiguration with your two 750's, perhaps using one them for data and the other as a backup of that data.

The only other thought I had (unless your 1Tb boot drive has a LOT of data on it right now) was to use TM to backup to just one of the 750's for now which would last quite a while- and it could be easily replaced by a 1.5Tb later when they are stable and reliable.

If neither of those options floats your boat, then I guess the JBOD is the only reasonable alternative.