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Conference decwet::advfs_support

Title:AdvFS Support/Info/Questions Notefile
Notice:note 187 is Freq Asked Questions;note 7 is support policy
Moderator:DECWET::DADDAMIO
Created:Wed Jun 02 1993
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1077
Total number of notes:4417

995.0. "System disk re-creation" by HGOVC::NANDAN () Fri Jan 31 1997 02:36

    
    A customer was using 3.2C which was upgraded to 3.2G. They are 
    using AdvFS both for the / & /usr. This along with the swap uses 
    up one disk. By the way, the disks are configured with RAID 5.
    
    They are a telephone company & since it is a critical application, 
    they are doing dummy recovery exercises.
    
    They want to recover the system disk exactly as before, say a 
    system disk crash. The idea is that it would contain a lot of 
    configuration details, which they should not have to go thru' 
    again. They would like to avoid LSM & mirroring.
    
    The customer therefore did a 'vdump' of the system disk. Now they 
    replace a fresh set of disks (since its RAID).
    
    Then using a 3.2G CDROM, they try to create a similar 
    configuration as the earlier disks (disklabels, etc are okay).
    
    ------------------------------------------------------------------
    Problem 1
    ---------
    When they try to 'vrestore' the root (64MB) especially, they get 
    an error for the root. (But restoration of the /usr seems to go 
    through).
    #vrestore -x /
    vrestore : Date of the vdump save-set : Wed Jan 22 13:52:41 1997
    vrestore : <.>; Out of disk space
    vrestore : Do you want to abort the restore ? (yes or no)
    
    Since they were experimenting anyway, they increased the size of 
    the root partition.
    
    Now, the restoration goes thru', but some daemons do not start up.
    
    I do not find any examples of this in the manual. So is this idea, 
    or concept of using 'vdump' & 'vrestore' for the system disk 
    wrong ?
    
    Problem 2
    ---------
    The other thing they wanted to try out was to boot with the 3.2G 
    CDROM, go into 'System Management' and then use 'vrestore' to 
    restore the system.
    
    The versions of 'vdump' & 'vrestore' on the CDROM are 1.3, whereas 
    the 'vdump' taken with 3.2G is at 4.0.
    
    So, they are not able to use this method.
    
    ------------------------------------------------------------------
    
    I am sure there are many who have done this before. Can someone 
    please give some advice on this.
    
    Thanks in advance.
    
    Nandan
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995.1DECWET::DADDAMIODesign Twice, Code OnceFri Jan 31 1997 13:3411
    Problem 1 sounds like they have sparse files which are getting filled
    in by vdump/vrestore so they end up being larger after being restored. 
    This is probably why they are running out of space. If they know which
    files, you can use dd with the conv=sparse option to convert them back
    to sparse - HOWEVER dd will remove all blocks of zeros from the file.
    If some of these happen to be real data that is supposed to be
    allocated then you could have problems when using those files. The good
    news is that this problem was fixed in V4.0 so the files are restored 
    to exactly the same size as they previously were.
    
    There are replies to your previous note (985) that deal with problem 2.
995.2AdvFS system disk restoration...HGOVC::NANDANSat Feb 01 1997 21:4022
    Daddamio,

    Thank you for your response.

    Unfortunately, the customer cannot move to 4.0 for some time.

    Anyway, going back to the heart of the problem, i.e restoration
    of the system disk, can you please give me your advice.

    Is the concept right ?
    
    >>They want to recover the system disk exactly as before, say a 
    >>system disk crash. The idea is that it would contain a lot of 
    >>configuration details, which they should not have to go thru' 
    >>again. They would like to avoid LSM & mirroring.
    
    I would very much appreciate a response from you, or the other
    readers.

    Thanks in advance.

    Nandan
995.3additional notes of my experience...DAIVC::SUGIYONOSun Feb 02 1997 23:5630
NANDAN,
  
    >> Unfortunately, the customer cannot move to 4.0 for some time.

	Your Customer no need to move to the V4.0a in this case. When I told 
you that I used the V4.0a CD-ROM in 985.1, I just used it to restore the tape 
content. So, I still got the DU V3.2G (after the restoration completed)
as before. Here's what I've done exactly (just for your reference):

	1. Boot using V4.0a CD-ROM
	2. Choose UNIX Shell
	3. 	# cd /dev
		# MAKEDEV rz...  tz...  ( rz for the disk destination; 
					  tz for the tape drive)
	4. Disklabel the disk as appropriate (don't forget to use the option
		-t advfs as the disk destination will be used as boot disk)
	5. 	# mkfdmn -r /dev/rz0a root_domain (assume the detination is 
									rz0)
		# mkfset root_domain root
		# mount root_domain#root /tmp
		# vrestore -xvf /dev/nrmt0h -D /tmp
	6. Repeat the step 5 for other file system.

	Hope this will help you.


Regards,


Sugiyono
995.4Thanks very much...HGOVC::NANDANMon Feb 03 1997 20:239
    
    Sugiyono,
    
    Thank you for the detailed instructions. I have passed them on to the
    customer.
    
    I hope they will satisfy the user requirements.
    
    Nandan