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  • 1.  Using usbms0 for backups

    Posted Mon December 18, 2023 07:30 AM


    I know I can save a mksysb or savevg to /dev/usbms0 as per document

    Is it possible to store both the mksysb AND savevg data on the same USB device or will the bootable mksysb be overwritten by the savevg?

    p.s. I would try this but can't get to the system easily to put a USB drive in to test this :-(

    Glenn Robinson

  • 2.  RE: Using usbms0 for backups

    Posted Mon December 18, 2023 01:15 PM
    Edited by Ron Arms Wed December 20, 2023 02:37 PM

    They would overwrite each other.  Although we treat the RDX similar to tape it's truly a removable hard drive.

    One way to perform what you're looking to do would be if you had a filesystem in rootvg such as /backup  where a savevg is performed of user volume group that writes/saves to the /backup filesystem in rootvg, then the mksysb would capture the savevg file.   Note, the RDX drives are not overly fast so while the RDX makes a great device option for AIX mksysb bootable backups it's not great once you start having a terabyte or more of data.

    Since the RDX is a hard drive it can be mounted as read/write filesystem, just keep in mind as a bootable mksysb so you need to be careful what you're modifying.

    Note:  While you can use SMIT to view contents of mksysb to view contents of a user defined volume group I usually use "lssavevg -f /dev/usbms0 -s".  The smit system backup manager menu's seem to only work for AIX mksysb's.

    Ron Arms

  • 3.  RE: Using usbms0 for backups

    Posted Tue December 19, 2023 11:55 AM

    You should be able to create a mksysb of your system and then add as many savevgs of any other VGs as space allows.  The mksysb must be first because the first step for mksysb is to format the device/media.

    First do a mksysb to the usb device using the mksysb options of your choice.  Mksysb wipes out the current device content because mksysb formats the device as a UDFS file system.

    Once the mksysb to the device is complete, manually mount the USB device and you should see a typical AIX file system.  This is just enough AIX to boot from the USB device and perform a restore of rootvg.  The actual rootvg backup file if I remember correctly is under /usr/sys/inst.images.  The bacukp file is really just a customized file list from rootvg fed to the the backup command. 

    Pick a location for your savevg(s) files on the mounted USB device.  Create directories if desired.  Run savevg on each vg and outputting the savevg to a file on the usb device.

    To restore rootvg, boot from the USB and restore rootvg using options of your choice.  Once rootvg is restored, boot from the restored system, mount the USB device and restore the remaining savevgs as needed using typical restore vg procedures.

    Our environement has a number of remote AIX servers with a fairly small disk footprint leaving a lot of available space.  We also have mirrored or raided disks so a single disk failure doesn't force a recovery.  Rather than make a mksysb to USB device, we create a mkssyb file to an excluded local directory/file on each system.  We then transfer a copy of that mksysb backup file to another storage location typically in a different facility to provide an offsite backup.  Should a full system recovery be required, the remote mksysb copy is used to create a bootable mksysb USB from an existing mksysb file and then the bootable USB is used to restore the failed system.  The one requirement when making the USB recovery device is that the system on which the recovery USB is created must be at the same or higher AIX level.  This is becasue the bootable part of the recovery device is made from the running AIX, not from the content of the mksysb backup.   Does this sound like a poormans backup system?  That's exactly what it is.  HMC, NIM etc can all play a role if you have them.  

    One large advantage of the disk saves and only create USB as needed is not having to manage USB sticks inserting them into servers for backup.  This method can be automated with a few scripts such that no manual intervention is required unless recovery is required.  Downtime for backup is minimal.  The copy to remote storage doesn't have to be done during the backup period. etc. etc.


    Jim Rinn

  • 4.  RE: Using usbms0 for backups

    Posted Tue December 19, 2023 06:08 PM


    Thanks a lot, that helps a great deal.

    I am also implementing the copy of mksysb ISOs to a remote site so that I can use DD to copy to USB as required.


    Glenn Robinson

  • 5.  RE: Using usbms0 for backups

    Posted Wed December 20, 2023 10:33 AM

    We've used the RDX USB media for years in this fashion...

    Run the mksysb to the device, then run multiple savevg's to the same device.

    This has worked well at several sites for several years, from AIX 6.1 into current releases...

    However, our experience is that the media, although reportedly bootable, can't be booted to restore/load the mksysb.

    We recently attempted an AIX 7.2 upgrade from AIX 7.1; we had issues with the upgrade and could not boot/recover from the RDX media. Which required a manual rebuild, as we did not have bootable AIX media for our 7.1 installation.

    Your mileage may vary, and I hope it does, for the better.

    Bob Wyatt