illumos gate

Suppose you make a BE which starts with the string "ramdisk" - for example:

jeffpc@osiris:~$ beadm list
BE                       Active Mountpoint      Space Policy Created
hipster                  NR     /               14.5G static 2014-12-01 11:04
ramdisk-base-nd-1        -      -               114K  static 2014-12-01 10:48

Then, you mount it, and try to rebuild the boot archive:

jeffpc@osiris:~$ sudo beadm mount ramdisk-base-nd-1
Mounted successfully on: '/tmp/tmp.NKaWHc'
jeffpc@osiris:~$ df -h /tmp/tmp.NKaWHc/
Filesystem                    Size  Used Avail Use% Mounted on
rpool/ROOT/ramdisk-base-nd-1   38G   11G   27G  29% /tmp/tmp.NKaWHc
jeffpc@osiris:~$ sudo bootadm update-archive -v -R /tmp/tmp.NKaWHc/ ; echo $?
bootadm: /tmp/tmp.NKaWHc/ is on a ramdisk device
0

Note that the command did not fail. It just did nothing. If you don't specify

-v

, you will not see the message about ramdisk device. Of course, you can't boot with a busted boot archive.

A quick look at usr/src/cmd/boot/bootadm/bootadm.c reveals a function called

is_ramdisk

which attempts to determine whether the BE is on a ramdisk. It does so by comparing the special devices against a string ("/ramdisk") using

strstr

.

update_archive

calls

is_ramdisk

early on and if the device is determined to be a ramdisk, it just bails.

In my case, since "rpool/ROOT/ramdisk-base-nd-1" contains "/ramdisk" it is incorrectly deemed to be a ramdisk.

It looks like this bug has been around for a long time.