Re: 5.07 /etc/init Problem

From: Jeff Hyman (scolist_at_cactus.com)
Date: 04/14/05 

Date: 14 Apr 2005 15:58:09 -0400

Transpower typed (on Thu, Apr 14, 2005 at 11:16:26AM -0700):
------ clipped ----
| One more thing: the CTAR manual says it's completely compatible with
| TAR. If so, then why didn't my TAR restore work with the CTAR
| (uncompressed) tape?
|
| RWS
| transpower@aol.com

   CTAR is compatible with 'tar'. I consider this a good feature.
In most cases users would restore a 'tar' archive using 'ctar'.
However, when restoring a 'ctar' archive using standard 'tar' a few
things must be taken into consideration since 'ctar' out features and
out performs 'tar' in many ways:
1. Is the ctar archive compressed? In your case its not... so no problem.
2. Symlinks?
3. Device files?
4. Named pipe files?

In your case you want to simply restore '/etc/init'.
5. If SCSI, make darn sure the low-level SCSI blocksize matches
   what was used to create the tape.
   # tape getblk
   # tape -a 1024|512|0 setblk /dev/rStp0
     Search for string "setblk" below for details.

   From what I've read, your problem is not unique to CTAR.
I would bet that tar <==> tar would also be a problem
providing the hardware configurations matched.

   I want to let you know that this is no sales pitch to you.
CTAR has been around for over 2 decades and is a great
product to have on any system. BackupEDGE is also a fabulous
product. I am the LONE-TAR guy and do NOT want you or anyone
to think this is an effort to push LONE-TAR. I posted some
LONE-TAR FAQ's below to help... not sell.
You're already in good hands. Call 803-454-0300. Ask for Monica.
Tell her that Jeff Hyman says hi and that you need to talk to Steve.
I'll stay in the background to help should you need it.

Best Regards,
Jeffrey Hyman, CEO/President
                                 .--.
___________________________ .-. | | _____________________________________
 Lone Star Software Corp. | | | | .-. Home of World Famous LONE-TAR(tm)
 Cactus International, Inc. | |_| | | | Backup Software for UNIX and LINUX
   Sales: 800.525.8649 _ |___ |_| | 24x7 Support Available
 Support: 301.829.1622 _| ~- | ___| RESCUE-RANGER(tm) and AIR-BAG(tm)
 http://www.LONE-TAR.com \, _} | | Disaster Recovery Software
-------------------------- \( -- | | --------------------------------------
                                 | |

##############################################################################
KEYWORDS: 1021 tar cpio lone-tar lonetar compatible compatibility read restore

QUESTION: If LONE-TAR does not use 'tar' ... then why is it named LONE-TAR?

ANSWER: We intentionally maintain standard 'tar' compatibility. This creates
          more of a non-proprietary backup environment. Let's say that you
          have a LONE-TAR backup, and need to take this tape to another
          site that does NOT have LONE-TAR. Well... you could simply use
          the 'tar' command at the other site to restore your tape. There
          is no need to be locked into a situation where LONE-TAR is
          required on any system where you need to do a backup or restore.

          The reverse is also true. If you receive a tape that was created
          using regular 'tar'... then LONE-TAR can read it. LONE-TAR
          is widely used as an error recovery tool to get past bad spots
          on a 'tar' tape. Standard 'tar' leaves you dead in the water,
          whereas LONE-TAR has sophisticated ERROR RECOVERY capabilities
          to get past these bad spots in most cases.

NOTES: Compression must be turned OFF for a system to be able to restore
          a compressed LONE-TAR backup to a system that only has 'tar'.
          You can still 'list' a compressed LONE-TAR tape using 'tar',
          because LONE-TAR does _not_ compress the file headers.

##############################################################################
KEYWORDS: 1149 4mm dat portability compatibility convert conversion 8mm tape setblk toggle variable instead expected blocks received

RELEASE: LONE-TAR v3.2.4.1

QUESTION: My company is attempting to restore archive 4mm tapes that
          were created out in the field to our new server in house.
          I am receiving the following error:

          # lone-tar: received only {num} blocks, {num} bytes instead of
          expected {num} blocks
          Check blocking factor (try {num} ) or volume size not specified
          lone-tar: Offset was {num} K

          The end of the archive came unexpectedly.
          This resulted weither we performed a listing or a restore.

          What is causing this error and how do I fix it?

ANSWER: Three things must occur to successfully restore from a 4mm on
          one system, to a 4mm on another system:
          1. The low-level SCSI block size must match.
             # tape getblk /dev/your_device_name
             # grep SCSI_Blocksize /log/LAST_Master
             # ltmenu
             u --> c --> 2
          2. The tape drives themselves do not need to be the same,
             but MUST be "compatible". Model numbers, firmware, tape
             capacity issues are a good start.
          3. The 4mm "tapes" must be compatible between the two tape "drives".

          Use the 'tape', 'mt' or 'tapecntl' command to toggle the mode of
          your tape drive in the event the two tape drives modes do not match.
          # tape -a 1024 setblk /dev/your_device_name
          # tape -a 512 setblk /dev/your_device_name
          # tape -a 0 setblk /dev/your_device_name
          ... or ...
          # mt -f /dev/your_device_name status | grep block <-- LINUX
          # tapecntl -f 512 /dev/your_device_name <-- UW7
          
NOTES: Take a look at shell script '/usr/lone-tar/bu.tapeutil'
          specifically at function 'get_commands()'.

          To have LONE-TAR preset the low-level SCSI blocksize:
          # ltmenu
          e --> 8 --> 93 <Enter> e

REFERENCE: FAQ-1018 FAQ-1104
  CREATED: Thu May 16 14:55:27 EDT 2002 - JBH
###############################################################################

Relevant Pages

  • Re: 5.07 /etc/init Problem
    ... >> CTAR ... I was able to tar the files from the ... > minimal SCO system on the HD, ... In a ctar backup, if you had software compression enabled during backup, ...
    (comp.unix.sco.misc)
  • Re: Linux Backup Administration
    ... Gnutar and star provide extensions to the original tar (which did ... > relative pros and cons of cpio style vs. tar style backup? ... goal is to be able to restore an exactly identical system as fast ... The most likely reason to need the backup is that someone accidentally ...
    (Fedora)
  • RE: problem with restore
    ... If you take backup and try restore using tar, ... Note:- Make sure that you have rewinded the tape before trying to ...
    (RedHat)
  • tar vs dpkg --get-selections for backup scheme
    ... past with various backup programs like mondo to name one, ... Not sure how you can fit several tar to one cd but maybe one can use ... To restore, you would have to boot with a rescue cd like Knoppix, ... Install a base system, set the package selections with dpkg ...
    (Debian-User)
  • tar or dump and restore commands on Compaq Tru64 UNIX or Unix - restore from tape?
    ... They have a script I assume that runs a backup tape every night of just one ... So no idea if they are using tar or dump. ... assuming their either are using a tar or dump command / script. ... a restore from a tar file assuming they are using tar. ...
    (comp.unix.admin)