- Joined
- Jun 24, 2010
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- 1,689
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- Encinitas, CA USA
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First I must say that I love Time Machine. It is hands down the easiest backup and restore system I have ever used and I have tried many. It has saved me several times from various disk failures. Time Machine was designed for and works extremely reliably when connected to a local MacOS HSF journaled file system. However, there is a weakness in the implementation on a NAS that makes it quite fragile when confronted with sudden interruptions such as power failures. In order to operate on a NAS Apple uses a kind of virtual disk called a sparsebundle. This sparsebundle can easily be corrupted and this is what happened to me.
After several power hits during a recent storm my Synology NAS started beeping and telling me that my volume had crashed. After another shutdown and restart it restored the NAS but when Time Machine subsequently tried to verify the volume it failed and stopped backing up. I tried several command line procedures that I found on the net but they all failed as well. The net effect was to loose my entire local backup archive.
I would like to point out that this is not an issue with Synology as it also happens on other NAS systems even Apple's own Time Capsule.
As a quick stopgap measure I attached a 3TB external drive and added it to my Time Machine configuration. It took about 4 hours to backup my computer again and I started to breath easier.
I then told Time Machine to restart on the NAS volume. It took 24 hours to erase the old useless sparsebundle (about 3.5TB going back to 2015) and then told me it was going to take an additional 24 hours (estimated) to complete another new initial backup. At this point I reassessed the situation and decided that it was not worth the time nor the risk to try to maintain a TM backup on the NAS.
I had previously thought the 3TB was insufficient to handle my backups but it turns out that after a full backup I still have 1TB left. This turns out to provide sufficient local storage for the near term protection. Since I also have an active CrashPlan backup that goes back several years I have more than enough protection against longer term problems.
I originally purchased the Synology NAS when I also upgraded my 1TB internal data storage disk to 3TB. Because I wanted to have at least a 2X capacity for my Time Machine archive and at the time the largest capacity single drives were only 4TB which were also quite expensive. But now with 6TB, 8TB and even 10TB disks it no longer makes sense to me to use a NAS for TM backups.
-louie
After several power hits during a recent storm my Synology NAS started beeping and telling me that my volume had crashed. After another shutdown and restart it restored the NAS but when Time Machine subsequently tried to verify the volume it failed and stopped backing up. I tried several command line procedures that I found on the net but they all failed as well. The net effect was to loose my entire local backup archive.
I would like to point out that this is not an issue with Synology as it also happens on other NAS systems even Apple's own Time Capsule.
As a quick stopgap measure I attached a 3TB external drive and added it to my Time Machine configuration. It took about 4 hours to backup my computer again and I started to breath easier.
I then told Time Machine to restart on the NAS volume. It took 24 hours to erase the old useless sparsebundle (about 3.5TB going back to 2015) and then told me it was going to take an additional 24 hours (estimated) to complete another new initial backup. At this point I reassessed the situation and decided that it was not worth the time nor the risk to try to maintain a TM backup on the NAS.
I had previously thought the 3TB was insufficient to handle my backups but it turns out that after a full backup I still have 1TB left. This turns out to provide sufficient local storage for the near term protection. Since I also have an active CrashPlan backup that goes back several years I have more than enough protection against longer term problems.
I originally purchased the Synology NAS when I also upgraded my 1TB internal data storage disk to 3TB. Because I wanted to have at least a 2X capacity for my Time Machine archive and at the time the largest capacity single drives were only 4TB which were also quite expensive. But now with 6TB, 8TB and even 10TB disks it no longer makes sense to me to use a NAS for TM backups.
-louie