Much of my life has been spent waiting for a computer to restart. No, that’s not a Windows joke, just an acknowledgment that I’ve installed or upgraded lots of systems from lots of vendors over the ages.  When it comes to the Install/Upgrade Experience (IUE), I can readily say that Apple has done a phenomenal job with Mac OS X.

Learn how I created ten new Leopard machines - check out their detailed install history, from simple DVD upgrades, to Disk Utility clones, and even a full restore from a Time Machine Backup.

10-LeopardInstalls-small.pdf :  1 MB

10-LeopardInstalls-large.pdf  : 21 MB

Update:  January 28, 2008

But there’s one more thing:  my new Mac Pro, RAID disks, and more Time Machine information.

If you want to skip having to wade though the fluff, here’s my executive summary.  What happens if you temporarily pause using one Time Machine backup disk, begin using a second, and then switch back to the first?  Does Time Machine “catch up” on those missed days? Well, for a sample of one, I can say ... yes.

It was May 2007 when I hatched my master plan to upgrade my old Quicksilver PowerMac.  But by the time I’d saved enough dough, rumors were floating around about an imminent refresh of the product.  So I waited, much longer than I though I’d have to, so long in fact that I finally made the decision to buy 1 minute after the 2008 Macworld keynote, even if there wasn’t a new model.

Imagine my surprise when on a Tuesday morning (8 January) the week before the keynote I noticed that the Apple Store was down - that usually means just one thing, new products! And so I placed my order that morning for a dual quad-core Mac Pro, almost 6 years after I ordered the Quicksilver.

Hornet, as I’ve come to call it, arrived 16 January configured with minimal disk and memory, as by now we all know that it’s far more cost effective to install your own. So over the next few days I added another 4 GB of memory and three more hard disks to completely fill the drive bay.  My plan called for mirroring the startup volume, and using the remaining two physical disks as the Time machine backup volume.

This was a snap with Disk Utility.  I used the first two disks, each 1 TB in size, to make a 1 TB RAID 1 mirror array.  This provides for data redundancy but is no substitute for a normal backup plan. I then used the two Mac Pro installer DVDs to rebuild the new Macintosh HD volume, which weighed in at 16 GB total at the completion of the install.

The last two internal disks were each 500 GB, so I used Disk Utility to make a 1 TB “concat” volume, sometimes called a JBOD.  This is Hornet’s Time Machine volume.

Now, I wanted to see how Time Machine handled switching between two Time Machine disks, so before using the internal Time Machine volume I first attached a FireWire 800 external disk and named it TM Backup 1.  I let Time Machine use this volume until January 20th, as this shows:

[lusol@hornet:/Volumes/TM Backup 1/Backups.backupdb/Hornet] ls -al

total 8

drwxr-xr-x@ 15 root  lusol  510 Jan 26 22:26 .

drwxr-xr-x+  3 root  lusol  102 Jan 17 17:48 ..

drwxr-xr-x@  6 root  lusol  204 Jan 17 02:14 2008-01-17-021445

drwxr-xr-x@  6 root  lusol  204 Jan 18 00:57 2008-01-18-005658

drwxr-xr-x@  6 root  lusol  204 Jan 19 01:19 2008-01-19-011414

drwxr-xr-x@  6 root  lusol  204 Jan 20 00:58 2008-01-20-005723

drwxr-xr-x@  6 root  lusol  204 Jan 20 01:58 2008-01-20-015741

drwxr-xr-x@  6 root  lusol  204 Jan 20 02:58 2008-01-20-025811

drwxr-xr-x@  6 root  lusol  204 Jan 20 03:59 2008-01-20-035848

drwxr-xr-x@  6 root  lusol  204 Jan 20 04:59 2008-01-20-045854

drwxr-xr-x@  6 root  lusol  204 Jan 20 06:01 2008-01-20-060028

drwxr-xr-x@  6 root  lusol  204 Jan 26 21:41 2008-01-26-214126

drwxr-xr-x@  6 root  lusol  204 Jan 26 22:21 2008-01-26-222151

lrwxr-xr-x   1 root  lusol   17 Jan 26 22:21 Latest -> 2008-01-26-222151

hornet:/Volumes/TM Backup 1/Backups.backupdb/Hornet] sudo du -s -h 2008-01-20-060028/

129G    2008-01-20-060028/

So, 129 GB on TMB1 as of 20 January.

Then I stopped using the external FireWire disk and enabled the internal volume, called TM Backup 2.  I used it until the 26th, when I switched back to TMB1 - note the last two Time Machine backups above from the 26th - we’ll get back to them shortly. In the time period from the 20th through the 26th I loaded lots of new iTunes media, mostly movies and podcasts, so I expected these later Time Machine backups to be considerably larger than 129 GB.

This directory listing shows the Time Machine backups from the 20th through the 26th on TMB2 after the switch:

[admin@hornet:/Volumes/TM Backup 2/Backups.backupdb/Hornet] ls -al

total 8

drwxr-xr-x@ 36 root  lusol  1224 Jan 28 11:21 .

drwxr-xr-x+  3 root  lusol   102 Jan 20 19:14 ..

drwxr-xr-x@  6 root  lusol   204 Jan 20 20:50 2008-01-20-204941

drwxr-xr-x@  6 root  lusol   204 Jan 21 00:46 2008-01-21-004618

drwxr-xr-x@  6 root  lusol   204 Jan 22 00:42 2008-01-22-004055

drwxr-xr-x@  6 root  lusol   204 Jan 23 00:34 2008-01-23-003411

drwxr-xr-x@  6 root  lusol   204 Jan 24 00:58 2008-01-24-005831

drwxr-xr-x@  6 root  lusol   204 Jan 25 00:21 2008-01-25-002118

drwxr-xr-x@  6 root  lusol   204 Jan 26 00:22 2008-01-26-002204

drwxr-xr-x@  6 root  lusol   204 Jan 27 00:21 2008-01-27-002132

...

drwxr-xr-x@  6 root  lusol   204 Jan 28 11:21 2008-01-28-112137

lrwxr-xr-x   1 root  lusol    17 Jan 28 11:21 Latest -> 2008-01-28-112137

Let’s check the backup size from early morning on the 27th:

hornet:/Volumes/TM Backup 2/Backups.backupdb/Hornet] sudo du -s -h 2008-01-27-002132/

150G    2008-01-27-002132/

Ah, now I’m up to 150 GB on TMB2, and increase of 21 GB from TMB1.  So what I expected (wanted?) to see when I resumed using TMB1 was an initial backup size of 21 GB, and that’s exactly what happened (sorry, no screen shot, how remiss of me). But here’s the du summary to prove it:

hornet:/Volumes/TM Backup 1/Backups.backupdb/Hornet] sudo du -s -h 2008-01-26-214126/

150G    2008-01-26-214126/

So there you have, for a sample of one, Time Machine picked up where it left off after a 6 day timeout.