NetBSD Backup with dump

[acottag]

Hello!

I am studying and working on NetBSD 5.0.2 (following the Guide) in order to use it as my primary OS, but I am somehow a novice to Unix and understand that NetBSD requires attention to details.

I installed NetBSD on a primary - 3rd - partition and I need to make a backup, but the theme is not explained in the Guide in more detail.

I'm using the machine internal 100GB ATA HD and an external, removable, USB connected 120GB ATA HD to backup.

The machine I am using is described at "www.daemonforums.org/showthread.php?t=1882#post34048".

I understood from reading man pages that the # dump command is the main resource to make backups on NetBSD.

I tried the # dump command but I have something wrong and I don't know what it is, although I have tried with several different options.

1. Accessing the system from "Boot single user", the disks are

wd0

and

sd0

, as given by # dmesg.

Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007, 2008, 2009
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 5.0.2 (GENERIC) #0: Sat Feb  6 17:53:27 UTC 2010
	builds@b7.netbsd.org:/home/builds/ab/netbsd-5-0-2-RELEASE/i386/201002061851Z-obj/home/builds/ab/netbsd-5-0-2-RELEASE/src/sys/arch/i386/compile/GENERIC
total memory = 1022 MB
avail memory = 993 MB
timecounter: Timecounters tick every 10.000 msec
timecounter: Timecounter "i8254" frequency 1193182 Hz quality 100
Hewlett-Packard Pavilion dv5000 (ES259EA#AB9)      (F.54)
mainbus0 (root)
cpu0 at mainbus0 apid 0: AMD 686-class, 1989MHz, id 0x20f42
cpu0: AMD PowerNow! Technology 2000 MHz
cpu0: available frequencies (Mhz): 800 1600 1800 2000
cpu0: erratum 89 present
cpu0: WARNING: errata present, BIOS upgrade may be
cpu0: WARNING: necessary to ensure reliable operation
ioapic0 at mainbus0 apid 1: pa 0xfec00000, version 21, 24 pins
acpi0 at mainbus0: Intel ACPICA 20080321
acpi0: X/RSDT: OemId <PTLTD ,  RSDT  ,06040000>, AslId < LTP,00000000>
acpi0: SCI interrupting at int 9
acpi0: fixed-feature power button present
acpi0: fixed-feature sleep button present
timecounter: Timecounter "ACPI-Fast" frequency 3579545 Hz quality 1000
ACPI-Fast 32-bit timer
acpilid0 at acpi0 (LID, PNP0C0D): ACPI Lid Switch
acpibut0 at acpi0 (PWRB, PNP0C0C): ACPI Power Button
hpqlb0 at acpi0 (QLB, HPQ0006): HP Quick Launch Buttons
WMID (PNP0C14) at acpi0 not configured
npx1 at acpi0 (MATH, PNP0C04)
npx1: io 0xf0-0xfe irq 13
npx1: reported by CPUID; using exception 16
pcppi1 at acpi0 (SPKR, PNP0800)
pcppi1: io 0x61
midi0 at pcppi1: PC speaker (CPU-intensive output)
sysbeep0 at pcppi1
attimer1 at acpi0 (TIME, PNP0100): AT Timer
attimer1: io 0x40-0x43 irq 0
pckbc1 at acpi0 (KBC0, PNP0303): kbd port
pckbc1: io 0x60,0x64 irq 1
pckbc2 at acpi0 (MSE0, SYN0120): aux port
pckbc2: irq 12
acpiec0 at acpi0 (EC0, PNP0C09): ACPI Embedded Controller
acpiec0: io 0x62,0x66
acpidalb0 at acpi0 (MBTA, PNP0C32-1): Direct Application Launch Button
acpidalb1 at acpi0 (MBTB, PNP0C32-2): Direct Application Launch Button
acpidalb2 at acpi0 (MBTC, PNP0C32-3): Direct Application Launch Button
acpidalb3 at acpi0 (MBTD, PNP0C32-4): Direct Application Launch Button
acpibat0 at acpi0 (BAT1, PNP0C0A-1): ACPI Battery (Control Method)
acpibat0: battery info: Hewlett-Packard , Lion, Primary  
acpiacad0 at acpi0 (ACAD, ACPI0003): ACPI AC Adapter
acpitz0 at acpi0 (THRM): critical 94.0C passive 0.0C, passive cooling
apm0 at acpi0: Power Management spec V1.2
attimer1: attached to pcppi1
pckbd0 at pckbc1 (kbd slot)
pckbc1: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard
pms0 at pckbc1 (aux slot)
pms0: Synaptics touchpad version 6.2
pms0: Palm detect, Multi-finger
pckbc1: using irq 12 for aux slot
wsmouse0 at pms0 mux 0
pci0 at mainbus0 bus 0: configuration mode 1
pci0: i/o space, memory space enabled, rd/line, rd/mult, wr/inv ok
pchb0 at pci0 dev 0 function 0
pchb0: vendor 0x1002 product 0x5950 (rev. 0x01)
ppb0 at pci0 dev 1 function 0: vendor 0x1002 product 0x5a3f (rev. 0x00)
pci1 at ppb0 bus 1
pci1: i/o space, memory space enabled
vga1 at pci1 dev 5 function 0: vendor 0x1002 product 0x5955 (rev. 0x00)
wsdisplay0 at vga1 kbdmux 1: console (80x25, vt100 emulation), using wskbd0
wsmux1: connecting to wsdisplay0
drm at vga1 not configured
ppb1 at pci0 dev 5 function 0: vendor 0x1002 product 0x5a37 (rev. 0x00)
pci2 at ppb1 bus 2
pci2: no spaces enabled!
ohci0 at pci0 dev 19 function 0: vendor 0x1002 product 0x4374 (rev. 0x00)
ohci0: interrupting at ioapic0 pin 19
ohci0: OHCI version 1.0, legacy support
usb0 at ohci0: USB revision 1.0
ohci1 at pci0 dev 19 function 1: vendor 0x1002 product 0x4375 (rev. 0x00)
ohci1: interrupting at ioapic0 pin 19
ohci1: OHCI version 1.0, legacy support
usb1 at ohci1: USB revision 1.0
ehci0 at pci0 dev 19 function 2: vendor 0x1002 product 0x4373 (rev. 0x00)
ehci0: interrupting at ioapic0 pin 19
ehci0: dropped intr workaround enabled
ehci0: EHCI version 1.0
ehci0: companion controllers, 4 ports each: ohci0 ohci1
usb2 at ehci0: USB revision 2.0
piixpm0 at pci0 dev 20 function 0
piixpm0: vendor 0x1002 product 0x4372 (rev. 0x11)
piixpm0: interrupting at SMIpiixpm0: polling
iic0 at piixpm0: I2C bus
ixpide0 at pci0 dev 20 function 1
ixpide0: ATI Technologies IXP IDE Controller (rev. 0x00)
ixpide0: bus-master DMA support present
ixpide0: primary channel configured to compatibility mode
ixpide0: primary channel interrupting at ioapic0 pin 14
atabus0 at ixpide0 channel 0
ixpide0: secondary channel configured to compatibility mode
ixpide0: secondary channel interrupting at ioapic0 pin 15
atabus1 at ixpide0 channel 1
pcib0 at pci0 dev 20 function 3
pcib0: vendor 0x1002 product 0x4377 (rev. 0x00)
ppb2 at pci0 dev 20 function 4: vendor 0x1002 product 0x4371 (rev. 0x00)
pci3 at ppb2 bus 6
pci3: i/o space, memory space enabled
vendor 0x14e4 product 0x4319 (miscellaneous network, revision 0x02) at pci3 dev 2 function 0 not configured
cbb0 at pci3 dev 4 function 0: vendor 0x104c product 0x8031 (rev. 0x00)
fwohci0 at pci3 dev 4 function 2: vendor 0x104c product 0x8032 (rev. 0x00)
fwohci0: interrupting at ioapic0 pin 23
fwohci0: OHCI version 1.10 (ROM=0)
fwohci0: No. of Isochronous channels is 4.
fwohci0: EUI64 61:3f:02:00:a5:6d:40:7d
fwohci0: Phy 1394a available S400, 2 ports.
fwohci0: Link S400, max_rec 2048 bytes.
ieee1394if0 at fwohci0: IEEE1394 bus
fwip0 at ieee1394if0: IP over IEEE1394
fwohci0: Initiate bus reset
vendor 0x104c product 0x8033 (miscellaneous mass storage) at pci3 dev 4 function 3 not configured
vendor 0x104c product 0x8034 (SD Host Controller system) at pci3 dev 4 function 4 not configured
rtk0 at pci3 dev 6 function 0: Realtek 8139 10/100BaseTX (rev. 0x10)
rtk0: interrupting at ioapic0 pin 22
rtk0: Ethernet address 00:0f:b0:c1:eb:1a
rlphy0 at rtk0 phy 7: Realtek internal PHY
rlphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
cbb0: cacheline 0x8 lattimer 0x40
cbb0: bhlc 0x824008
cbb0: interrupting at ioapic0 pin 20
cardslot0 at cbb0
cardbus0 at cardslot0: bus 7
pcmcia0 at cardslot0
auixp0 at pci0 dev 20 function 5: vendor 0x1002 product 0x4370 (rev. 0x02)
auixp0: interrupting at ioapic0 pin 17
auixp0: soft resetting aclink
vendor 0x1002 product 0x4378 (modem communications, revision 0x02) at pci0 dev 20 function 6 not configured
pchb1 at pci0 dev 24 function 0
pchb1: vendor 0x1022 product 0x1100 (rev. 0x00)
pchb2 at pci0 dev 24 function 1
pchb2: vendor 0x1022 product 0x1101 (rev. 0x00)
pchb3 at pci0 dev 24 function 2
pchb3: vendor 0x1022 product 0x1102 (rev. 0x00)
pchb4 at pci0 dev 24 function 3
pchb4: vendor 0x1022 product 0x1103 (rev. 0x00)
isa0 at pcib0
fwohci0: BUS reset
fwohci0: node_id=0xc800ffc0, gen=1, CYCLEMASTER mode
ieee1394if0: 1 nodes, maxhop <= 0, cable IRM = 0 (me)
ieee1394if0: bus manager 0 (me)
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0
auixp0: ac97: Conexant CXT48 codec; reserved, headphone, 18 bit DAC, 18 bit ADC, no 3D stereo
auixp0: ac97: ext id a04<AC97_23,AMAP,SPDIF>
audio0 at auixp0: full duplex, mmap, independent
auixp0: codec spdif support detected but disabled for now
uhub0 at usb0: vendor 0x1002 OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 4 ports with 4 removable, self powered
uhub1 at usb1: vendor 0x1002 OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub1: 4 ports with 4 removable, self powered
uhub2 at usb2: vendor 0x1002 EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
uhub2: 8 ports with 8 removable, self powered
acpiacad0: AC adapter online.
ubt0 at uhub0 port 4
ubt0: Broadcom Corp HP Integrated Module, rev 2.00/1.00, addr 2
wd0 at atabus0 drive 0: <TOSHIBA MK1031GAS>
wd0: drive supports 16-sector PIO transfers, LBA addressing
wd0: 95396 MB, 193821 cyl, 16 head, 63 sec, 512 bytes/sect x 195371568 sectors
wd0: 32-bit data port
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
wd0(ixpide0:0:0): using PIO mode 4, Ultra-DMA mode 5 (Ultra/100) (using DMA)
atapibus0 at atabus1: 2 targets
cd0 at atapibus0 drive 0: <TSSTcorpCD/DVDW TS-L532M, Y54A600011, HR08> cdrom removable
cd0: 32-bit data port
cd0: drive supports PIO mode 4, DMA mode 2
cd0(ixpide0:1:0): using PIO mode 4, DMA mode 2 (using DMA)
Kernelized RAIDframe activated
pad0: outputs: 44100Hz, 16-bit, stereo
audio1 at pad0: half duplex
hpqlb0: registering on wskbd0
boot device: wd0
root on wd0a dumps on wd0b
root file system type: ffs
umass0 at uhub2 port 4 configuration 1 interface 0
umass0: JMicron USB to ATA/ATAPI Bridge, rev 2.00/1.00, addr 2
umass0: using SCSI over Bulk-Only
scsibus0 at umass0: 2 targets, 1 lun per target
sd0 at scsibus0 target 0 lun 0: <SAMSUNG, HM121HC, 0-10> disk fixed
sd0: 111 GB, 16383 cyl, 16 head, 63 sec, 512 bytes/sect x 234441648 sectors

2. Results with # fdisk
2.1 The result from # fdisk wd0 is:

Disk: /dev/rwd0d
NetBSD disklabel disk geometry:
cylinders: 193821, heads: 16, sectors/track: 63 (1008 sectors/cylinder)
total sectors: 195371568

BIOS disk geometry:
cylinders: 1023, heads: 255, sectors/track: 63 (16065 sectors/cylinder)
total sectors: 195371568

Partition table:
0: NTFS, OS/2 HPFS, QNX2 or Advanced UNIX (sysid 7)
    start 63, size 41945652 (20481 MB, Cyls 0-2610)
1: Extended partition (sysid 5)
    start 41945715, size 136327590 (66566 MB, Cyls 2611-11096)
2: NetBSD (sysid 169)
    start 178273305, size 17098263 (8349 MB, Cyls 11097-12161/80/63), Active
3: <UNUSED>
Extended partition table:
E0: Linux native (sysid 131)
    start 41945778, size 2104452 (1028 MB, Cyls 2611-2741)
        PBR is not bootable: All bytes are identical (0x00)
E1: Linux swap or Prime or Solaris (sysid 130)
    start 44050293, size 8385867 (4095 MB, Cyls 2742-3263)
        PBR is not bootable: All bytes are identical (0x00)
E2: Linux native (sysid 131)
    start 52436223, size 52436097 (25604 MB, Cyls 3264-6527)
        PBR is not bootable: All bytes are identical (0x00)
E3: Linux native (sysid 131)
    start 104872383, size 73400922 (35840 MB, Cyls 6528-11096)
        PBR is not bootable: All bytes are identical (0x00)
First active partition: 2
Drive serial number: 3146693518 (0xbb8ebb8e)

2.2 The result from # fdisk sd0 command is:

Disk: /dev/rsd0d
NetBSD disklabel disk geometry:
cylinders: 16383, heads: 16, sectors/track: 63 (1008 sectors/cylinder)
total sectors: 234441648

BIOS disk geometry:
cylinders: 1023, heads: 255, sectors/track: 63 (16065 sectors/cylinder)
total sectors: 234441648

Partition table:
0: NTFS, OS/2 HPFS, QNX2 or Advanced UNIX (sysid 7)
    start 63, size 41945652 (20481 MB, Cyls 0-2610)
1: Extended partition (sysid 5)
    start 41945715, size 136327590 (66566 MB, Cyls 2611-11096)
2: NetBSD (sysid 169)
    start 178273305, size 17098263 (8349 MB, Cyls 11097-12161/80/63), Active
3: <UNUSED>
Extended partition table:
E0: Linux native (sysid 131)
    start 41945778, size 2104452 (1028 MB, Cyls 2611-2741)
        PBR is not bootable: All bytes are identical (0x00)
E1: Linux swap or Prime or Solaris (sysid 130)
    start 44050293, size 8385867 (4095 MB, Cyls 2742-3263)
        PBR is not bootable: All bytes are identical (0x00)
E2: Linux native (sysid 131)
    start 52436223, size 52436097 (25604 MB, Cyls 3264-6527)
        PBR is not bootable: All bytes are identical (0x00)
E3: Linux native (sysid 131)
    start 104872383, size 73400922 (35840 MB, Cyls 6528-11096)
        PBR is not bootable: All bytes are identical (0x00)
First active partition: 2
Drive serial number: 3146693518 (0xbb8ebb8e)

3. Results with # disklabel
3.1 The result from # disklabel wd0 command is:

# /dev/rwd0d:
type: unknown
disk: TOSHIBA MK1031G
label: 
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 16
sectors/cylinder: 1008
cylinders: 193821
total sectors: 195371568
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0		# microseconds
track-to-track seek: 0	# microseconds
drivedata: 0 

16 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 a:  16834608 178273305     4.2BSD   2048 16384     0  # (Cyl. 176858*- 193559*)
 b:    263655 195107913       swap                     # (Cyl. 193559*- 193820)
 c:  17098263 178273305     unused      0     0        # (Cyl. 176858*- 193820)
 d: 195371568         0     unused      0     0        # (Cyl.      0 - 193820)
 e:  41945652        63       NTFS                     # (Cyl.      0*-  41612*)
 i:   2104452  41945778 Linux Ext2      0     0        # (Cyl.  41612*-  43700*)
 j:   8385867  44050293       swap                     # (Cyl.  43700*-  52019)
 k:  52436097  52436223 Linux Ext2      0     0        # (Cyl.  52020*- 104039)
 l:  73400922 104872383 Linux Ext2      0     0        # (Cyl. 104040*- 176858*)

3.2 The result from # disklabel sd0 command is:

# /dev/rsd0d:
type: unknown
disk: TOSHIBA MK1031G
label: 
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 16
sectors/cylinder: 1008
cylinders: 193821
total sectors: 195371568
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0		# microseconds
track-to-track seek: 0	# microseconds
drivedata: 0 

16 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 a:  16834608 178273305     4.2BSD   2048 16384     0  # (Cyl. 176858*- 193559*)
 b:    263655 195107913       swap                     # (Cyl. 193559*- 193820)
 c:  17098263 178273305     unused      0     0        # (Cyl. 176858*- 193820)
 d: 195371568         0     unused      0     0        # (Cyl.      0 - 193820)
 e:  41945652        63       NTFS                     # (Cyl.      0*-  41612*)
 i:   2104452  41945778 Linux Ext2      0     0        # (Cyl.  41612*-  43700*)
 j:   8385867  44050293       swap                     # (Cyl.  43700*-  52019)
 k:  52436097  52436223 Linux Ext2      0     0        # (Cyl.  52020*- 104039)
 l:  73400922 104872383 Linux Ext2      0     0        # (Cyl. 104040*- 176858*)

4. The result with # dump is:

# dump -0 -f /dev/rsd0da /dev/rwd0da
DUMP: Found /dev/rwd0a on / in /etc/fstab
DUMP: Date of this level 0 dump: Sun Nov 28 12:56:08 2010
DUMP: Date of last level 0 dump: The epoch
DUMP: Dumping /dev/rwd0a (/) to /dev/sd0a
DUMP: Label: none
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (PAss II) [directories]
DUMP: estimated 4144592 tape blocks on 106.27 tape(s)
DUMP: Volume 1 started at: Sun Nov 28 15:05:44 2010
DUMP: write error 20 blocks into volume 1
DUMP: Do you want to restart ("yes" or "no") no
DUMP: The ENTIRE dump is aborted

Please help.

With best regards.

[J65nko]

CAVEAT: I don't have a running NetBSD system so be careful.

If I would want to dump my OpenBSD system on wd0a

# disklabel wd0
# /dev/rwd0c:
type: ESDI
disk: ESDI/IDE disk
label: WDC WD3200AAKS-2
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 255
sectors/cylinder: 16065
cylinders: 38913
total sectors: 625142448
rpm: 3600
interleave: 1
boundstart: 63
boundend: 81915435
drivedata: 0 

16 partitions:
#                size           offset  fstype [fsize bsize  cpg]
  a:         81787372               63  4.2BSD   2048 16384    1 # /
  b:           128000         81787435    swap                   
  c:        625142448                0  unused

Just like your NetBSD system, my OBSD is in one single filesystem/label : wd0a

# ls -l /
drwxr-xr-x   2 root    wheel       512 Apr  4  2010 altroot
drwxr-xr-x   2 root    wheel      1024 Apr  4  2010 bin
-r-xr-xr-x   1 root    wheel     42612 Apr  5  2010 boot
-rw-r--r--   1 root    wheel   8635425 Apr  5  2010 bsd
-rw-r--r--   1 root    wheel   8658947 Apr  5  2010 bsd.mp
-rw-r--r--   1 root    wheel   7318475 Apr  5  2010 bsd.rd
drwxr-xr-x   3 root    wheel     23552 Nov 29 15:58 dev
drwxr-xr-x  28 root    wheel      2560 Nov 29 15:58 etc
drwxr-xr-x   7 root    wheel       512 Apr  5  2010 home
drwxr-xr-x   2 root    wheel       512 Apr  4  2010 mnt
drwx------   6 root    wheel      1024 Jun 20 18:42 root
drwxr-xr-x   2 root    wheel      1536 Apr  4  2010 sbin
drwxrwxrwt   6 root    wheel       512 Nov 29 15:58 tmp
drwxr-xr-x  17 root    wheel       512 Mar 26  2010 usr
drwxr-xr-x  24 root    wheel       512 May 11  2010 var

Mount your USB 120 GB disk on /mnt. ( I don't know the NetBSD commands to do so ...)

Now backup all directories to files using the -a flag, except /mnt.
Reason: you don't want to backup your backup in progress!
The autosize -a flag is needed to backup to file.

dump -0af /mnt/bin.dump /bin
dump -0af /mnt/boot.dump /boot
dump -0af /mnt/dev.dump /dev
....
dump -0af /mnt/usr.dump /usr
dump -0af /mnt/var.dump /var

For the files /boot, bsd and bsd.mp:

dump -0af /mnt/kernels.dump /bsd /bsd.mp /bsd.rd

If you have a second system that you can connect to, you don't have to do a dump for each directory separately, but could dump the complete wd0a filesystem over the network through ssh or nc.

[thirdm]

This is my back up script I use at home that uses dump on OpenBSD. If you can figure out scsh, maybe it will help you. Or if someone else reads scheme, maybe he or she will notice something I'm overlooking. I find dump a little intimidating myself, or at least thinly documented, though this script does create a backup that I can see interactively with restore. You probably want to ignore the dump level command line argument I allow, since I haven't thought through how that would work with the file name I write to yet (if you think about it, you'll see it wouldn't be a good idea to supply an argument other than 0 to my script).

#!/usr/local/bin/scsh -s
# Back up important file systems to poe using dump.
# Pass the dump level on the command line (0-9).
!#

(define (suffix mnt-point)
  (if (string=? mnt-point "/")
      "_root"
      (string-map (lambda (c) (if (char=? c #\/) #\_ c))
                  mnt-point)))

(for-each
 (lambda (mnt)
   (run
     (|
       (/sbin/dump -h0 -u
                   ,(string-append "-" (arg command-line-arguments 1 "0"))
                   -f -
                   ,mnt)
       (ssh "-i" /home/thirdm/.ssh/id_rsa
            thirdm@192.168.2.2 dd ,(string-append "of=backups/holly_backup"
                                                  (suffix mnt)
                                                  ".dmp")))))
 '("/" "/home" "/var" "/usr/ports"))

[acottag]

Progress Report 3/Dec/2010

.I could not get dump command to use special devices, like wd0a and sd0a, yet; so, in order to make a system backup I had to use dump with -f option and files-to-dump, i.e, by specifying directories and file names.

.For the previous reason, dump doesn't fit very well when it's necessary to exclude directories and files from the backup being done. Beside that, dump is quite tape oriented, as a great number of options relate to manipulating tape media.

.As an alternative, I believe dar - Disk ARchiver is a better solution, when doing disk based backups: it's supposed to be used with disks, not with tape media; it supports incremental backups, as dump; it provides proper options for including and/or excluding directories and files.

.At this moment, I am trying to build a bootable cdrom that shoul provide # dar, using command # mklivecd; I believe this makes sense, for the situation which there is not a bootable NetBSD installation on the machine to restore (the worst case).

All the best.