Hello. Can anyone give me some pointers for comprehensive information about tape backups? A brief bit of background: I have linux servers running mostly FC2, some RH9 and a couple of RH73. One of the servers has some autochangers attached - a DLT, an LT01 and an LTO2. I have scripts which automate which tape to load based on the day and what's being backed up. Control of the changers is done using mtx, control of the drives is done with mt, and the backups are done using xfsdump and dump from remote machines. The main problem I have is that I seem to be running out of space on the tape a long time before I've stored anywhere near as much data on there as the tape should hold - for instance, I'm trying to back up about 150G on an LTO2 tape which has native capacity of 200G, and it's failing with a message suggesting the tape is full. There are a couple of specific things I'm trying to find out; maybe someone knows the answers to these and can answer me direct :o) What does "block size" mean on a tape (DLT and LTO). Is it the same as old disks, where each file fills up at least one block, even if it's much smaller than a block? If I make this smaller, will more small files fit on the tape? How do I get the tape drive to definitely use it's internal compression hardware? I don't think it's working and I need it to be. How can I check this from linux? Some of the auto-changers have displays on the front that specify whether compression is being used, but others don't. Is there any way of finding out how much of the tape has been used by a backup - in terms of actual tape, not in terms of how much data there was in the backup? I really want to be able to work out how much space is left on the tape. Answers to any and all of the above questions very much appreciated. Thanks. Paul. - : send the line "unsubscribe linux-admin" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
