On Fri, Aug 16, 2002 at 10:07:54AM +0300, Conny Gyllendahl wrote:
> Now for my last question for this time: what are the pros and cons, if
> any, for using tar or (ufs)dump? Are there any reasons or situtations
> for choosing one over the other?
You say "ufs(dump)", so I'm assuming recent Solaris. The calculation
is different for Linux.
ufsdump plus:
- Gets all file system/file attributes, period, no ifs ands or
buts, even ones you don't know are there. :-)
- Does not touch atime on files.
- Does not require running as root.
- In my experience, on file systems with large numbers of small
files, estimates and incrementals are much faster than GNU tar.
ufsdump minus:
- No exclude list.
- No splitting the file system.
- Data is not portable to other OS's.
tar plus:
- Flexibility. Excludes, splitting.
- 100% portable, ubiquitous. (But see also tar minus)
tar minus:
- Touches atime.
- In my experience, on file systems with large numbers of small
files, estimates and incrementals can take a long time.
- "Portable, but": GNU tar output with very long paths/names is
only guaranteed to be readable by another GNU tar of "similar"
version. Reading with non-GNU tar (or older GNU tar) may
generate errors, or garbled paths/names. Depending on the
versions involved, things get interesting at name lengths of 100
or 256, and path lengths of 256 or 1024. This is a very minor
minus, you just need to be aware.
- Has to run as root (no, I don't lose any sleep worrying about
runtar exploits! :-)
Speed folklore:
In my experience, on full backups, on modern Solaris kit, GNU tar
is a bit faster than ufsdump, *not* slower. Disks have gotten a
lot faster (helps the more-random seeks that tar has to do), ufs
and the processors have gotten faster (so ufs isn't "in the way"
any more), and ufsdumps's initial mapping (wonderful for
'ufsrestore -i') is just time down the drain from amanda's
POV.
There, no religion here, I think. Look at the plus/minus lists and
make up your own mind. As the Perl folk say, TMTOWTDI.
--
Jay Lessert [EMAIL PROTECTED]
Accelerant Networks Inc. (voice)1.503.439.3461
Beaverton OR, USA (fax)1.503.466.9472
