UNIX for Dummies Questions & Answers

One of our production systems has a slice called "oldslice" that periodically runs low on space during normal operation. We have minimum requirements for online data retention, and whoever sized this slice didn't give it much wiggle room, so it periodically runs low on space. I'm getting tired of archive files every other week in response to low space alerts.

I discovered(I inherited these systems ) that there is an unused slice on the same drive that is several times larger than then problematic one.

I've used newfs to make a filesystem on the unused slice, and have mounted it under /mnt/newslice .

Now I want to duplicate oldslice's contents to newslice. There are a number of ways to do this, but I want the most reliable and least resource intensive one to do it while the system is active.

This looks promising if it doesn't use too many resources -

Code:

 
cd dir1 && tar -cf – . | (cd dir2 && tar -xpvf -)

ideas?

A couple 'is that the best solution' ideas:I suppose if you copy one raw partition to the next, you do not get a usable larger file system!

Using two processes as you did, not 'cp -rp `ls -A` target_dir', will usually speed things, as UNIX is single buffered. If you multiplex the file list to many pairs, you might double the speed again, but files might be a bit more page-interlaced (fragmented). Of course, if they are on the same spindle, cable or controller, that might not speed up much if at all.


If you copy by mod age of inode oldest first, the files will be defragmented, as well, and the future fragmentation tends to occur at the end, in younger files. I am still waiting the fs to end all fs, where the stuff moves and defrags in the background to be mirrored or raid N, compressed, backed up on remote nodes, possibly many, possibly compressed in all or all but one copy, some quiescent files not even copied locally, and with the files relocated so the activity of each device versus the bandwidth of the device is leveled (less active files on larger, slower devices, including CD/DVD/WORM), with old versions also preserved as backup, either mandatory or space available.