Backup without using SMS API!

Question

Hi,
I am using regular FS APIs opendir(), readdir(), stat() to collect items to backup files from NSS volumes and then during backup I am using regular FS APIs open(), read(), etc to read data streams and using z APIs, zGetInfo(), zModiInfo(), zAddTrustee(), zGetTrustee(), etc to read/write Trustee and extended attributes.
My question is, how different will it be as opposed to using SMS APIs for the same above stated operations with respect to
1) performance
2) being able to backup/restore all possible trustee and extended attributes information
3) future support
Thanks,
Manoj

Answer 1

In the absence of SMS, the zAPIs will be the way to do things for NSS, and since you are removing an layer of abstraction, should be faster. Also, the extended attributes are exposed via zAPI. It also means you can handle compressed streams, creepy apple stuff that can be exposed via AFP. While NSSifying things, you should also look at the modified file list capabilities. That can eliminate the enumeration and reconciliation phase most incremental backup processes require. For example, if you had to dredge through the metadata of a 8 million file file system just to find 2000 modified files.... the MFL is very useful. In fact, if you are looking to do "continuous" backup - which I would be willing to pay for :-) so do a good job, please - using feature like this allow for rapid acquisition of the deltas.
-- Bob