Resizing Time Machine Space

[AlecEdworthy]

Hello,

After a fair bit of reading around I have come to the conclusion that when setting up a ReadyNAS Duo running a recent firmware then the size you specify in Backup -> Time Machine is used for two things,

1. Setting the maximum space all Time Machine backups can use on the ReadyNAS (i.e. the quota on the ReadyNAS for the Time Machine share)
2. Setting the maximum space any single Time Machine backup can use (i.e. the maximum size of the sparse bundle)

I believe that it is possible to alter the maximum size that all Time Machine backups can use on the ReadyNAS by just revisiting Backup -> Time Machine and altering the setting, but this would not alter the maximum size of each sparse bundle within the Time Machine share. For instance you could set it to 200Gb initially, attach two Macs to it for Time Machine use (creating two 200Gb max size sparse bundles) and then alter the setting to 400Gb to end up with each sparse bundle being able to take 200Gb but a total allocation of 400Gb for the pair. Can someone confirm this for me please?

I have also read on some sites[1] that Time Machine (certainly in 10.6.4 and earlier) would automatically resize the sparse bundle beyond the initial size limitation specified once the bundle became full (though there are hacks to do with locking the Info file along with another file to stop this). I am not sure whether this really is the case (the sites suggest it is) and if so whether this behaviour has been altered in 10.6.5.

What I am wondering is, assuming that altering the setting in Backup -> Time Machine does alter the maximum size of the Time Machine share, and does so in a non-distructive way, then would it also be possible to manually increase the maximum size of a specific Time Machine sparse bundle using the command,

hdiutil resize -size <new_size> <name_of_sparse_bundle>

I have tried this on a normal sparse bundle (i.e. one created using Disk Utility rather than Time Machine itself) and it seemed to work. I am now wondering if this really would work? My reason for asking is that I don't really want to dedicate too much of my ReadyNAS to Time Machine now but it would be nice to have the safety and security of knowing that if I need to increase the allocation in the future then it is possible.

Thanks, Alec

1. e.g. http://discussions.info.apple.com/message.jspa?messageID=11933687

[mdgm]

Hello,

After a fair bit of reading around I have come to the conclusion that when setting up a ReadyNAS Duo running a recent firmware then the size you specify in Backup -> Time Machine is used for two things,

1. Setting the maximum space all Time Machine backups can use on the ReadyNAS (i.e. the quota on the ReadyNAS for the Time Machine share)
2. Setting the maximum space any single Time Machine backup can use (i.e. the maximum size of the sparse bundle)

I believe that it is possible to alter the maximum size that all Time Machine backups can use on the ReadyNAS by just revisiting Backup -> Time Machine and altering the setting, but this would not alter the maximum size of each sparse bundle within the Time Machine share. For instance you could set it to 200Gb initially, attach two Macs to it for Time Machine use (creating two 200Gb max size sparse bundles) and then alter the setting to 400Gb to end up with each sparse bundle being able to take 200Gb but a total allocation of 400Gb for the pair. Can someone confirm this for me please?

Yes. The limit for the individual sparsebundle is set when it's created. The collective limit can be changed later on.

Welcome to the forum!

[AlecEdworthy]

Yes. The limit for the individual sparsebundle is set when it's created. The collective limit can be changed later on.

Thank you. Do you think my second supposition, regarding enlarging the individual sparse bundles, is also true?

Welcome to the forum!

Thanks mdgm! I have been doing lots of reading of the forums in the last few days, I only received my ReadyNAS on Tuesday ReadyNAS.com seems to be a pretty amazing place, lots of user driven support but also lots of help, support and guidance from Netgear's own support staff. It's good to see a product being actively developed and supported like this rather than what you often find elsewhere - sell the item, throw up a few FAQs, a software update every now and again and concentrate on the next sale.

Alec

[mdgm]

Do you think my second supposition, regarding enlarging the individual sparse bundles, is also true?

Not sure. If possible you'd probably need to copy the file to your computer, make the changes there, delete the sparsebundle on the NAS, then copy the modified version back. You could google to see if it is possible to resize Time Machine sparsebundles. Best to work on a copy so if you muck things up you can quickly copy the sparsebundle again and try again on another copy. This procedure would not be supported by NetGear.

Thanks mdgm! I have been doing lots of reading of the forums in the last few days, I only received my ReadyNAS on Tuesday ReadyNAS.com seems to be a pretty amazing place, lots of user driven support but also lots of help, support and guidance from Netgear's own support staff. It's good to see a product being actively developed and supported like this rather than what you often find elsewhere - sell the item, throw up a few FAQs, a software update every now and again and concentrate on the next sale.

I agree. I'm a happy ReadyNAS customer like you.

[chirpa]

ReadyNAS.com seems to be a pretty amazing place, lots of user driven support but also lots of help, support and guidance from Netgear's own support staff. It's good to see a product being actively developed and supported like this rather than what you often find elsewhere - sell the item, throw up a few FAQs, a software update every now and again and concentrate on the next sale.

Glad to hear this, makes me smile