Amount of files Backuped on to tape

Thread Tools Search this Thread
Top Forums UNIX for Advanced & Expert Users Amount of files Backuped on to tape
# 1  
Old 09-26-2002
Question Amount of files Backuped on to tape

My question is how much can you actually backup to a 160m tape and a 112m tape? i am trying to split all files and directories to it own section and what i am trying to do is find out much megabytes can each tape store so i know which tape to use.
# 2  
Old 09-27-2002
It is impossible to say. The reason - different drives use different compression (as does software). One day you might put 2GB on a tape, the next day, 4GB. It matters on what you tell the system to use to do the backup (ufsdump, dd, tar, 3rd party backup software, ...) and what kind of compression the tape drive has. You might get a closer (ballpark) figure if you had posted the OS, backup software being used, and hardware make/model of the tape drive.


What tape device address do I use for for my 4mm(DAT) or my
8mm drive?

The answer is not generic and requires

>>>>>> 4mm Cartridge Storage Capacity* <<<<<<<<<<

Tape Lgth Low Density High Density
(/dev/rmt/0l) (/dev/rmt/0m, 0h, or 0c)

60 Meters 1.3 Gbyte 3.25 Gbyte*
90 Meters 2.0 Gbyte 5.0 Gbyte*

* High density mode uses the data compression capability of the drive.
Compression will vary depending on the type of data stored; typical
compression is 2.5:1.

>>>>>> 8mm Cartridge Storage Capacity and device name to use* <<<<<<<<<<

Scaling this down appropriately, for the 14GB and 160m tapes (and 2.3):
/dev/rmt/0l - ~3.5GB (uncompressed 8200 mode)
/dev/rmt/0m - ~7GB (uncompressed 8500 mode)
/dev/rmt/0h - ~7GB (uncompressed 8500 mode)
/dev/rmt/0c - 14GB (compressed 8500 mode)

Scaling this down appropriately, for the 14GB and 160m tapes (and 2.4):
/dev/rmt/0l - ~3.5GB (uncompressed 8200 mode)
/dev/rmt/0m - ~7GB (uncompressed 8500 mode)
/dev/rmt/0h - 14GB (compressed 8500 mode)
/dev/rmt/0c - 14GB (compressed 8500 mode)

* For ALL tape devices, YOU DO NOT need to use l,m,h, or "c" to get
maximum storage capacity on your tape. The device driver will use the
highest capacity mode avail for the tape drive being used. Bottom line,
Keep It Simple and suggest /dev/rmt/0 or /dev/rmt/0n (no-rewind) for
normal operations. Use the l,m,h or c for portability between respective
tape devices.


What are the dump parameters for 4mm DAT drive for 4.1.3U1?

Here are the dump parameters for 4.1.3U1.

Native (non-compressed) mode:

dump 0ubdsf 96 54000 5200 /dev/rst0 /dev/xxx

The 96 specifies a blocking factor of 48 which is optimum for DAT/Loader
The 54,000 is the same density factor used for the 8mm drives
The 5,200 is used for size instead of 6000, because the DAT has a
capacity of 2GB rather than the 2.3GB capacity of 8mm drives.
The rst0 specifies non compression mode (this is very important)

compression mode:

The DAT drive supports compression. However, it is not possible to
determine how much data will fit on a tape. A typical value is twice
non-compression mode, but in some cases the data won't fit on the
tape and in many cases the data is muchmore compressible and tape
capacity will be wasted.

To be on the safe side, doubling the capacity is recommended. It should
be noted however that in some cases even this may not be conservative
enough, and that the only way to guarantee that the dump will not run
out of tape is to not use compression.

Doubling the size option (5200 in non-compressed mode) results in the
following command:

dump 0ubdsf 96 54000 10400 /dev/rst8 /dev/xxx

The 10400 specifies an anticipated capacity of 4Gbytes. Note the
use of /dev/rst8 instead of /dev/rst0.
# 3  
Old 11-25-2003
If I have an 8mm tape drive using a 160m tape on Solaris 8, what are the ufsdump parameters and which device driver should I use to get the proper compression to tape? I think I need to use the /dev/rmt/0hn to get maximum compression or the /dev/rmt/0mn to get moderate compression. Correct?
# 4  
Old 11-25-2003
The 8mm tape driver will always give you the max capacity. It ignores the bits in the minor number pertaining to density. However c indicates compressed and that is the max for drivers that care. Do a "man -s7i mtio" for the full list.

Sun's official recommendation is to use /dev/rmt/0 or /dev/rmt/0n or whatever. If you do a: "ls -lL /dev/rmt/0*" and look at the minor numbers, you will see that /dev/rmt/0 and /dev/rmt/0c are the same thing.

With every tape drive that I have ever seen, compression is either on or off. I don't believe that any tape drive will allow you to request different levels of compression.
# 5  
Old 11-25-2003
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Delete X amount of similar files in a directory

Need a Unix command to save the last 20 versions of a file in a specific directory and delete everything else. Date is irrelevant. Anyone aware of such an animal? In my test, I came up with: ls -t1 /tmp/testfile* | tail -n +20 | xargs rm I don’t quite trust the author though! (1 Reply)
Discussion started by: rwsherman
1 Replies

2. Solaris

files in tape

unix1{owadmin}% tar tvf /dev/rmt/1 -rw-rw-rw- 1021/10 0 Sep 11 17:54 2011 TinahPF_Far_32bit.segy tar: directory checksum error unix1{owadmin}% i know in this tape 3 files not only one file so what can i do to view 3 files and what is this error mean ( tar: directory checksum error... (2 Replies)
Discussion started by: ayman
2 Replies

3. Shell Programming and Scripting

How to tar large amount of files?

Hello I have the following files VOICE_hhhh SUBSCR_llll DEL_kkkk Consider that there are 1000 VOICE files+1000 SUBSCR files+1000DEL files When i try to tar these files using tar -cvf backup.tar VOICE* SUBSCR* DEL* i get the error: ksh: /usr/bin/tar: arg list too long How can i... (9 Replies)
Discussion started by: chriss_58
9 Replies

4. Shell Programming and Scripting

What amount of store occupy only files in a directory?

Hello I'm trying to do an exercise programming in bash where I have to get only the store of files in a directory but NOT all capacity of the directory. I probe with: du -sh "$directory"*` but I get all the capacity and I probe with ls command but I couldnt. Are there any way to get only files... (2 Replies)
Discussion started by: adiegorpc
2 Replies

5. AIX

Fastest way to count big amount of files in sub directory

Hi, what happened is we want to count all the files in a directory and inside this directory got many folders and so take long time to count it. Already run for about few minutes but still not done. The command we use to count is find . -type f | wc -l Just wondering if there is any other... (9 Replies)
Discussion started by: ngaisteve1
9 Replies

6. Filesystems, Disks and Memory

Appending files to a tape drive

I've starting playing with a tape drive for the first time. Its a new one, an IBM Ultrium LTO 4. After initially copying a file to the tape with tar cvf /dev/st0 /root/dummy, all subsequent files appended take an increasing amount of time with tar rvf /dev/st0 /root/dummyX. Is it normal for each... (2 Replies)
Discussion started by: jeriryan87
2 Replies

7. UNIX for Dummies Questions & Answers

Restoring tape files...

Hi all, I have kinda inherited this problem, but was wondering if anyone else had any ideas. Currently all our backup rentention periods are set to 2 weeks, so that we can cycle through tapes (save money etc...). Anyhow the guys next door in IT, decided one day long long ago, that it would... (0 Replies)
Discussion started by: B14speedfreak
0 Replies

8. Shell Programming and Scripting

deleting a varying amount of lines from a list of files

I did search the posts for info on this and while there were some in the ballpark, none addressed this specifically. (also I tried to post this once it said I was logged out, so hopefully I'm not sending a duplicate here). I have a set of files (250 +/-) where I need to delete the first "$x"... (4 Replies)
Discussion started by: benair
4 Replies

9. AIX

retrieving files from Tape

I have AIX5.1 I have tried to retrieve a file from tape with no sucsess. I had this posted in the newbies section but I think I should have tried here. I did get some good info there though on where to start. This Is what I did. My back line is so... cat /rd/tmp/backuplist.full | cpio -ocvBdum... (1 Reply)
Discussion started by: rocker40
1 Replies

10. UNIX for Dummies Questions & Answers

Dumping files to tape

Can anyone please help.... how can I dump just a single file to tape using the ufsrestore command!!! I'm a newbie to unix and It's driving me mad.. Thanks in advance. (2 Replies)
Discussion started by: Jonathan
2 Replies
Login or Register to Ask a Question