10 minute read

Used metadata saved by ‘’ to recreate host filesystems

SYNOPSIS [-d 0-9] [-h] [-v]
$SADMIN/bin/ - v2.3
Posted 2021-06-04 - Updated 2021-06-04
Supported on Linux, Aix


Linux - Recreating the filesystems and populate /etc/inittab

I use to work at a company where we use lvm a lot (Logical Volume Manager), every disk added to a system was assigned a lvm partition. It was easy to add new disks to an existing (or new) volume group. We would then enlarge the filesystems that needed space and we were done. We could all do that online without downtime or disruption. If you are using the LVM in a similar fashion then this utility could be interesting for you. If you’ve lost completely your server content, then with script you would be able to recreate all the filesystems that you had before the crash with the right size, permission and ownership (owner/group), ready to begin the restore of your data. If this seem interesting for you read on.

  • Every day the ‘’ script run and generate one output file name “$SADMIN/dat/dr/[hostname]_fs_save_info.dat”.
  • The ‘’ script is part of the ‘’ that is scheduled to run daily from the client crontab (/etc/cron.d/sadm_client).
  • The output file of ‘’ become the input file of this script.

In our example, we will use the file that was produced on a system name “gotham”, so the file name is “$SADMIN/dat/dr/gotham_fs_save_info.dat”. This file is use to recreate all filesystems of the specified volume group. The recreated filesystems will have the same permission, owner and group as on the original server. This script will not recreate the user or the group that was on the original server, we assume that this will be done prior to running this script. The example below will demonstrate how to recreate the filesystems that were on the volume group name “datavg”.

Here is the output file that was on produced on “gotham” server:

$ cat $SADMIN/dat/dr/gotham_fs_save_info.dat
# SADMIN - Filesystem Info. for system gotham.Host
# File was created by on Fri Dec  7 11:13:54 EST 2018
# This file is use in a Disaster Recovery situation
# The data below is use by to recreate filesystems
# ---------------------------------------------------------------------

You can modify this file prior to running the script.

  • If you don’t want a filesystem to be created, you can remove the line or change the volume group name.
  • You can also change the name of the filesystem, the size, owner, group or permission.
  • You can even change the filesystem type, the script support ext2, ext3, ext4 and xfs.

If we look in our Disaster Recover directory in the lvm file ($SADMIN/dat/dr/gotham_lvm.txt), we can find that :

  • The size occupy by the volume group ‘datavg’ is 15.99G.
  • That the volume group ‘datavg’ is only on one disk.
  • That is contain 3 filesystems (/coco1 coco2 /coco3) and one swap file (swap01).
# Command: /sbin/pvs
PV         VG         Fmt  Attr PSize  PFree 
/dev/sda2  rootvg     lvm2 a--u 55.75g  4.50g
/dev/sdb1  datavg_sdb lvm2 a--u 15.99g 11.65g
/dev/sdc1  datavg     lvm2 a--u 15.99g  9.99g   <<<<<
/dev/sdd1  data2vg    lvm2 a--u 96.00m 96.00m
# Command: /sbin/vgs
VG         #PV #LV #SN Attr   VSize  VFree 
data2vg      1   0   0 wz--n- 96.00m 96.00m
datavg       1   5   0 wz--n- 15.99g  9.11g     <<<<<
datavg_sdb   1   1   0 wz--n- 15.99g 11.65g
rootvg       1  14   0 wz--n- 55.75g  4.50g
# Command: /sbin/lvscan
ACTIVE            '/dev/datavg/coco1' [128.00 MiB] inherit  <<<<<
ACTIVE            '/dev/datavg/coco2' [1.00 GiB] inherit    <<<<<
ACTIVE            '/dev/datavg/coco3' [900.00 MiB] inherit  <<<<<
ACTIVE            '/dev/datavg/swap01' [4.00 GiB] inherit   <<<<<
ACTIVE            '/dev/datavg_sdb/datavgsdblv' [4.34 GiB] inherit
ACTIVE            '/dev/rootvg/home' [29.31 GiB] inherit
ACTIVE            '/dev/rootvg/opt' [1.00 GiB] inherit
ACTIVE            '/dev/rootvg/perf' [128.00 MiB] inherit
ACTIVE            '/dev/rootvg/root' [1.00 GiB] inherit
ACTIVE            '/dev/rootvg/swap00' [2.00 GiB] inherit
ACTIVE            '/dev/rootvg/tmp' [2.00 GiB] inherit
ACTIVE            '/dev/rootvg/usr' [7.81 GiB] inherit
ACTIVE            '/dev/rootvg/usrloc' [512.00 MiB] inherit
ACTIVE            '/dev/rootvg/var' [2.00 GiB] inherit
ACTIVE            '/dev/rootvg/admlv' [1.00 GiB] inherit

At Disaster Recovery site, recreate the ‘datavg’ volume group. Before running the script, let’s recreate the volume group “datavg”.

# pvcreate /dev/sdc1             (Device could be a disk or a partition)
Physical volume "/dev/sdc1" successfully created

# vgcreate datavg /dev/sdc1      (Create VG on the created device)
Volume group "datavg" successfully created

# vgs
VG         #PV #LV #SN Attr   VSize  VFree 
data2vg      1   0   0 wz--n- 96.00m 96.00m
datavg       1   0   0 wz--n- 15.99g 15.99g  (VG is on 1 PV, 0 LV on it and empty)
datavg_sdb   1   1   0 wz--n- 15.99g 11.65g
rootvg       1  14   0 wz--n- 55.75g  4.50g

Once the “datavg” volume group is created, we can now start the script:

Starting V2.2 - SADM Lib. V2.52
Server Name: - Type: LINUX
CENTOS 6.10 Kernel 2.6.32-754.6.3.el6.i686
Currently verifying the LVM version installed on system
Validating Program Requirements before proceeding ...

List of the volume group that are present in /sadmin/dat/dr/gotham_fs_save_info.dat
Enter the volume group name that you want to recreate the filesystems : 

This is a list of filesystems (and swap) that will created on datavg volume group
Type: swap  Mount Point:                                 LVName: swap01               
Type: ext4  Mount Point: /coco1                          LVName: coco1                
Type: ext3  Mount Point: /coco2                          LVName: coco2                
Type: ext4  Mount Point: /coco3                          LVName: coco3                

Do you want to proceed with the creation of all filesystems on datavg [Y/N] ? Y

Running : /sbin/lvcreate -L4096M -n swap01 datavg
Running : /sbin/mkswap -c /dev/datavg/swap01
Running : /sbin/swapon /dev/datavg/swap01
Running : Adding entry in /etc/fstab
Filesystem  created successfully

Running : /sbin/lvcreate -L128M -n coco1 datavg
Running : /sbin/mkfs.ext4 -b4096 /dev/datavg/coco1
Running : /sbin/fsck.ext4 -f /dev/datavg/coco1
Running : /sbin/tune2fs -c 0 -i 0 /dev/datavg/coco1
Running : /bin/mkdir -p /coco1
Running : Adding entry in /etc/fstab
Running : /bin/mount /coco1
Running : /bin/chown root:root /coco1
Running : /bin/chmod 0755 /coco1
Filesystem /coco1 created successfully

Running : /sbin/lvcreate -L1024M -n coco2 datavg
Running : /sbin/mkfs.ext3 -b4096 /dev/datavg/coco2
Running : /sbin/fsck.ext3 -f /dev/datavg/coco2
Running : /sbin/tune2fs -c 0 -i 0 /dev/datavg/coco2
Running : /bin/mkdir -p /coco2
Running : Adding entry in /etc/fstab
Running : /bin/mount /coco2
Running : /bin/chown jacques:staff /coco2
Running : /bin/chmod 0755 /coco2
Filesystem /coco2 created successfully

Running : /sbin/lvcreate -L900M -n coco3 datavg
Running : /sbin/mkfs.ext4 -b4096 /dev/datavg/coco3
Running : /sbin/fsck.ext4 -f /dev/datavg/coco3
Running : /sbin/tune2fs -c 0 -i 0 /dev/datavg/coco3
Running : /bin/mkdir -p /coco3
Running : Adding entry in /etc/fstab
Running : /bin/mount /coco3
Running : /bin/chown root:root /coco3
Running : /bin/chmod 0755 /coco3
Filesystem /coco3 created successfully

Script return code is 0
Script execution time is 00:01:30
Trim History /sadmin/dat/rch/gotham_sadm_dr_recreatefs.rch to 125 lines
Requested alert only if script fail (Won't send alert)
Trim log /sadmin/log/gotham_sadm_dr_recreatefs.log to 1000 lines
Sat Dec  8 11:17:38 EST 2018 - End of

Aix - Recreating the volume group and the filesystems it contain.

Every day when the ‘’ script run it create a minimum of two files in $SADMIN/dat/dr directory. One file is named ${HOSTNAME}_pvinfo.txt and we have another for each volume group present on the server (except ‘rootvg’). Let’s say for example we have the two files for an Aix server that had 2 volumes groups named ‘rootvg’ and ‘datavg’. Actually, we want to recover the volume group ‘datavg’ on another server at the disaster recovery site. The volume group ‘datavg’ contained one filesystem with the mount point ‘/test1’.

The server we have at the disaster recovery site have two disks :

  • The first one (hdisk0) is dedicated to the volume group ‘rootvg’ (the operating system).
  • The second one (hdisk1) is not used at the moment and will be use to recover the ‘datavg’ volume group.
# lspv
hdisk0      	0002dd2f26946375                	rootvg      	active
hdisk1      	0002dd2f24d98974                	None       	 

To recreate the ‘datavg’ volume group on disk ‘hdisk1’, we need to create a file with the diskname used for the restore. With your favorite editor create a file in ‘$SADMIN/dat/dr’ directory and name it ‘${HOSTNAME}_${VG}_restvg_disks.txt. In our example, the file name would be, ‘aixb50_datavg_restvg_disks.txt’ and would contain only one line.

# cat $SADMIN/dat/dr/aixb50_datavg_restvg_disks.txt

A different file have to be created for each volume group. This is a simple example, but imagine if you have multiple volume groups and multiple disks, the process is pretty simple. The thing you should take care of, is that the total disks size of all these disks should be equal or greater than the size of the VG to recreate. You can find the size you need to allocate in order to recreate the volume group in $SADMIN/dat/dr/HOSTNAME_pvinfo.txt.

Now let’s run the script to recreate our volume group and the filesystems in it.

root@aixb50(/sadmin/bin)# ./
2016.12.02 15:52:24 - =========================================================
2016.12.02 15:52:24 - Starting - Version 2.0 on aixb50
2016.12.02 15:52:25 - AIX AIX 5.3 IBM_AIX
2016.12.02 15:52:25 - =========================================================
2016.12.02 15:52:25 -  
2016.12.02 15:52:25 - AIX RESTORE OF A VOLUME GROUP
2016.12.02 15:52:25 -  
2016.12.02 15:52:25 - A Backup of these VG(s) exist in /sadmin/dat/dr :
2016.12.02 15:52:25 -  
2016.12.02 15:52:26 - Enter the volume group name that you want to restore :
2016.12.02 15:52:37 - Based on the content of /sadmin/dat/dr/aixb50_datavg_restvg_disks.txt
2016.12.02 15:52:37 - Here is the list of the destination disk(s) used for the restore
2016.12.02 15:52:37 -  hdisk1
2016.12.02 15:52:37 -  
2016.12.02 15:52:37 -  
2016.12.02 15:52:37 - Now ready to restore volume group datavg using the following disk(s)
2016.12.02 15:52:37 -  hdisk1
2016.12.02 15:52:38 -  
Do you want to proceed with the restore [Y/N] ? y

2016.12.02 15:52:44 - Restoring Volume Group datavg using backup file named :
2016.12.02 15:52:44 - /sadmin/dat/dr/aixb50_datavg.savevg
2016.12.02 15:52:44 -  
2016.12.02 15:52:44 - The backup will be restore onto these disk(s) :
2016.12.02 15:52:44 -  hdisk1
2016.12.02 15:52:44 -  
2016.12.02 15:52:44 - Command running is
2016.12.02 15:52:44 - restvg -q -f/sadmin/dat/dr/aixb50_datavg.savevg  hdisk1 
2016.12.02 15:52:44 -  
Will create the Volume Group:   datavg
Target Disks:   hdisk1
Allocation Policy:
        Shrink Filesystems: 	no
        Preserve Physical Partitions for each Logical Volume:   no
New volume on /sadmin/dat/dr/aixb50_datavg.savevg:
Cluster size is 51200 bytes (100 blocks).
The volume number is 1.
The backup date is: Fri Dec  2 14:43:17 EST 2016
Files are backed up by name.
The user is root.
x       	98 ./tmp/vgdata/vgdata.files20540
x       	98 ./tmp/vgdata/vgdata.files
x     	3313 ./tmp/vgdata/datavg/filesystems
x        	0 .
x     	2446 ./tmp/vgdata/datavg/
The number of restored files is 6.
x      	341 ./tmp/vgdata/datavg/
The total size is 6296 bytes.
2016.12.02 15:53:17 -  
2016.12.02 15:53:18 - =========================================================
2016.12.02 15:53:18 - Script return code is 0
2016.12.02 15:53:19 - Script execution time is 00:00:54
2016.12.02 15:53:19 - Trimming /sadmin/dat/rch/aixb50_sadm_dr_recreatefs.rch to 125 lines
2016.12.02 15:53:20 - User requested mail only if script fail - Will not send mail
2016.12.02 15:53:20 - Trimming /sadmin/log/aixb50_sadm_dr_recreatefs.log to max. 5000 lines.
2016.12.02 15:53:20 - Fri Dec  2 15:53:20 EST 2016 - End of
2016.12.02 15:53:20 - =========================================================
2016.12.02 15:53:20 -  

After the restore, with can see that the volume group ‘datavg’ have been recreated on ‘hdisk1’. We had the filesystem ‘/test1’ on that volume group and it as been also recreated.

        root@aixb50(/sadmin/bin)# lspv
        hdisk0      	0002dd2f26946375                	rootvg      	active
        hdisk1      	0002dd2f24d98974                	datavg      	active
        root@aixb50(/sadmin/bin)# lsvg
        root@aixb50(/sadmin/bin)# lspv -l hdisk1
        LV NAME           	LPs 	PPs 	DISTRIBUTION      	MOUNT POINT
        fslv08            	3   	3   	00..03..00..00..00	/test1
        loglv01           	1   	1   	00..01..00..00..00	N/A
        root@aixb50(/sadmin/bin)# df /test1
        Filesystem	512-blocks  	Free   %Used	Iused %Iused Mounted on
        /dev/fslv08   	393216	    392496	1%    	4 	    1%  /test1
        root@aixb50(/sadmin/bin)# ls -l /test1
        total 0
        drwxr-xr-x	2 root 	system      	256 Dec 02 15:53 lost+found

it is worth mentioning that raw devices are included in the backup and are restore by this script.

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Options Description
[ -d 0-9 ] Set debug level from 0 to 9 (Default is 0)
[ -h ] Display this help and exit.
[ -v ] Output version information and exit.
-i option -i


  • The “$SADMIN” environment variable must be defined and contains the root directory of the SADMIN tools (normally /opt/sadmin). It should be already done, the setup script have updated the ‘/etc/profile.d/’ and the ‘/etc/environment’ files.
  • The SADMIN configuration file, is needed and loaded in memory at the beginning of every scripts. This file should already exist and contains your SADMIN configuration and preference setting.
  • For Shell script the Shell Library is used and for Python script the Python Library is used.


Exit Code Description
0 An exit status of zero indicates success.
1 Failure is indicated by a nonzero value, typically ‘1’.


Jacques Duplessis
Any suggestions or bug report can be submitted at the support page

Copyright © 2021 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later
This is free software, you are free to change and redistribute it.
There is NO WARRANTY to the extent permitted by law.

SEE ALSO - Save system filesystems information in order to recreate them from scratch. - Clients end of day housekeeping and producing system information files - Purge old log,rch,nmon files and check $SADMIN permission - Collect hardware & software information about the system
System Information File - Documentation about the system information file - Get System information and creates a HTML web page of it.