Thank you Steve.
Archive for the 'Apple' Category
Just found out that my Time Machine SparseBundle is corrupt. I thought that it would be cool to save some money and hack Time Machine to enable backups to a Network Share on my home NAS instead of buying Time Capsule. It worked perfectly for a month or so, but I’ve done some changes on my home network and a couple of abrupt disconnects caused major havoc on it and eventually that was the cause of the corruption. Just found this info on this thread:
The technical reason why Apple limits Time Machine to 10.5 AFP volumes appears to be to prevent disk image corruption. There were additional features added to AFP in 10.5 to support Time Machine. These presumably allow the disk image engine to force disk image journal data to write out all the way to the disk. Without such features, a network interruption can result in a corrupted filesystem on the disk image despite journaling. Remember, journaling relies on the journal being written all the way to disk before the changes take place. If you can’t guarantee that (e.g., because of network/NAS buffering) then the journal is useless. Time Machine appears to rely heavily on disk journaling to deal with network drop-outs, interrupted backups, and the like. Take this away and your data is at risk.
If the NAS you are using supports these features it should report them to the OS and you should natively be able to choose that volume. If you have to trick the OS to use the volume it means the NAS does not support it.
To summarize: if you care about your backup data you should avoid using non-natively supported AFP servers.
I would be interested to know if somebody got it right with non-AFP 10.5 NAS (ie, Samba or NFS hack). I am now using a local attached USB disk.