Sponsored Content
Full Discussion: Optimal block size in dd
Operating Systems HP-UX Optimal block size in dd Post 302429430 by methyl on Monday 14th of June 2010 11:53:02 AM
Old 06-14-2010
Even with "conv=sync" a "dd" to tape should be of a structured file. My "cpio" and "tar" won't do files above 2Gb. We don't know what O/S version you have.
The optimum block size to tape depends on the properties of the tape deck and driver.
May be better to use proper backup software, checking whether it will handle very large files of 8Gb or more.
 

8 More Discussions You Might Find Interesting

1. Filesystems, Disks and Memory

block size

Hi, Somehow i have forgotten a comand that displays me the block size of the unix filesystem. Can someone letme know this command regards penguin (5 Replies)
Discussion started by: linuxpenguin
5 Replies

2. UNIX for Dummies Questions & Answers

How to know the OS Block size

Hello Unix guru's I want to check my OS Block size for the Solaris 8 Following is one of the line from df -g command. Can anybody help to interpret the same. /u03 (/dev/vx/dsk/oradg/vol03): 8192 block size 8192 frag size 205463552 total blocks 50433792... (1 Reply)
Discussion started by: Dilippatel
1 Replies

3. UNIX for Dummies Questions & Answers

block size

Hi All, drwxr-xr-x 2 root root 4096 May 31 14:47 test Please let me know here 4096 indicating what? Thanks & Regards, Bache (1 Reply)
Discussion started by: bache_gowda
1 Replies

4. UNIX for Dummies Questions & Answers

Remove header from files: optimal performance

I need to concatenate about a thousand files (using a loop) on a UNIX server. Also, each file has a header row which is to be removed. Which of the following would give better performance? tail+2 <filename> or sed '1,1d' <filename> Or is there another, faster way? Thanks, Kaus (4 Replies)
Discussion started by: kausmone
4 Replies

5. Red Hat

What is the optimal approach to reboot the linux server

Hi All, Our Linux server were rebooted 723 days before and now We have decided to reboot the server due to server performance. Could someone advise us what is the optimal duration of a server reboot ? Thanks for your time. Best Regards, Arun (2 Replies)
Discussion started by: arunap44
2 Replies

6. UNIX for Advanced & Expert Users

Physical disk IO size smaller than fragment block filesystem size ?

Hello, in one default UFS filesystem we have 8K block size (bsize) and 1K fragmentsize (fsize). At this scenary I thought all "FileSytem IO" will be 8K (or greater) but never smaller than the fragment size (1K). If a UFS fragment/blocksize is allwasy several ADJACENTS sectors on disk (in a ... (4 Replies)
Discussion started by: rarino2
4 Replies

7. Red Hat

O/s block size

Hi Guys, I am running Linux 2.6.18-164.el x86_64 how do i check the block size? Thanks in advance... (1 Reply)
Discussion started by: Phuti
1 Replies

8. HP-UX

About Block Size and Fragment Size

Accordingly a lot of manuals - if you have block size 8KB and trying to write a 1KB file to the block, as result you waste 7KB of the block space. But recently I noticed about Fragments of File Block. In same case if you have File Block 8KB and Fragment size 1KB - you can save your block space,... (6 Replies)
Discussion started by: jess_t03
6 Replies
TAR(1)							      General Commands Manual							    TAR(1)

NAME
tar - tape archiver SYNOPSIS
tar [ key ] [ name ... ] DESCRIPTION
Tar saves and restores files on magtape. Its actions are controlled by the key argument. The key is a string of characters containing at most one function letter and possibly one or more function modifiers. Other arguments to the command are file or directory names specify- ing which files are to be dumped or restored. In all cases, appearance of a directory name refers to the files and (recursively) subdirec- tories of that directory. The function portion of the key is specified by one of the following letters: r The named files are written on the end of the tape. The c function implies this. x The named files are extracted from the tape. If the named file matches a directory whose contents had been written onto the tape, this directory is (recursively) extracted. The owner, modification time, and mode are restored (if possible). If no file argument is given, the entire content of the tape is extracted. Note that if multiple entries specifying the same file are on the tape, the last one overwrites all earlier. t The names of the specified files are listed each time they occur on the tape. If no file argument is given, all of the names on the tape are listed. u The named files are added to the tape if either they are not already there or have been modified since last put on the tape. c Create a new tape; writing begins on the beginning of the tape instead of after the last file. This command implies r. The following characters may be used in addition to the letter which selects the function desired. 0,...,7 This modifier selects the drive on which the tape is mounted. The default is 1. v Normally tar does its work silently. The v (verbose) option causes it to type the name of each file it treats preceded by the function letter. With the t function, v gives more information about the tape entries than just the name. w causes tar to print the action to be taken followed by file name, then wait for user confirmation. If a word beginning with `y' is given, the action is performed. Any other input means don't do it. f causes tar to use the next argument as the name of the archive instead of /dev/mt?. If the name of the file is `-', tar writes to standard output or reads from standard input, whichever is appropriate. Thus, tar can be used as the head or tail of a filter chain Tar can also be used to move hierarchies with the command cd fromdir; tar cf - . | (cd todir; tar xf -) b causes tar to use the next argument as the blocking factor for tape records. The default is 1, the maximum is 20. This option should only be used with raw magnetic tape archives (See f above). The block size is determined automatically when reading tapes (key letters `x' and `t'). l tells tar to complain if it cannot resolve all of the links to the files dumped. If this is not specified, no error messages are printed. m tells tar to not restore the modification times. The mod time will be the time of extraction. FILES
/dev/mt? /tmp/tar* DIAGNOSTICS
Complaints about bad key characters and tape read/write errors. Complaints if enough memory is not available to hold the link tables. BUGS
There is no way to ask for the n-th occurrence of a file. Tape errors are handled ungracefully. The u option can be slow. The b option should not be used with archives that are going to be updated. The current magtape driver cannot backspace raw magtape. If the archive is on a disk file the b option should not be used at all, as updating an archive stored in this manner can destroy it. The current limit on file name length is 100 characters. TAR(1)
All times are GMT -4. The time now is 04:13 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy