April 2009 Archives

Updated May 05, 2009 Additional information, clarifications and corrections have been added inline. After the publication of this blog post, I discussed an unrelated experience with the CrashPlan Technical Support team. They provided the information I've added here; this update concerns changes in product naming, decryption, decompression and a partial explanation for slow restore times.

One particular note about product offering and features: There is a consumer and business product, and within the consumer release, there are different versions. To help compare the consumer version, visit this web page. This article talks about CrashPlan Pro, which is the enterprise solution.

I've deployed CrashPlan Pro Server (CPPS) as a backup solution for a department here at Stanford. They use it for both their desktops and servers. As is best practice, I performed a dry-run restoration of their files kept a network-attached storage. I used the performance metrics to make a back-of-the-envelope guess at how this would compare if we used our direct-attached FireWire 800 device as the backup repository.

Nota bene:This article provides a solution for Leopard Server (10.5). Snow Leopard Server (10.6) introduces a kink that makes this solution a better fix for the problem described in this article.

Update: Apple Enterprise Support suggested a modification to the /etc/smb.conf file that seems to have addressed this problem. Citing this entry in the Samba man page the suggestion is to append "nt acl support = no" at the very end of this conf file. Ours now looks like this:

You can also find more information by reading the authoritative Samba3-HOWTO.pdf and review sections 16.4, 16.5.3-5 and 43.5 as they pertain to this configuration option.

Original posting:

Here's something I've been chewing on that's alarming. There seems to be an exceptional issue with Microsoft Excel's "Share Workbook" feature while serving a spreadsheet on a Mac OS X Server via both AFP and CIFS.

In short, if a couple of users collaborate simultaneously on a spreadsheet, it will radically (and dangerously) alter your ACLs and POSIX-style permissions, irrespective of the parent folder's settings.

Here's how to reproduce this. Much of this is arbitrary for the sake of illustration, but it should be reproducible with other variables.