mdconfig at system boot

Leander

Leander

Hi fellows,

Code: 
truncate -s 1G /mnt/VirtualDisk
chmod 0600 /mnt/VirtualDisk
mdconfig -a -t vnode -f /mnt/VirtualDisk

works perfectly, but problem is that I still need the same md setup after a reboot as well. Unfortunately the system doesn't remember the mdconfig setup. So I found /etc/rc.d/mdconfig and /etc/rc.d/mdconfig2 and I started to add the following into my rc.conf:
Code: 
rc_debug="YES"
rc_info="YES"
mdconfig_md2="-t vnode -f /mnt/VirtualDisk"
After adding this, I tried [cmd=]/etc/rc.d/mdconfig start[/cmd] and [cmd=]/etc/rc.d/mdconfig2 start[/cmd] but nothing helped, md2 wasn't listed by [cmd=]mdconfig -lv[/cmd] After scanning a bit through the rc.d/mdconfig scripts, I figured it may want to have the actual md_n_ device to start so I tried [cmd=]/etc/rc.d/mdconfig start md2[/cmd] and voila:
Code: 
FreeBSD [~]# mdconfig -lv
md0	swap	  512M
md1	vnode	 4096M	/var/swap

FreeBSD [~]# /etc/rc.d/mdconfig start md2
/etc/rc.d/mdconfig: DEBUG: run_rc_command: start_precmd: [ -n "${_mdconfig_list}" ] 
/etc/rc.d/mdconfig: DEBUG: load_kld: geom_md kernel module already loaded.
/etc/rc.d/mdconfig: DEBUG: run_rc_command: doit: mdconfig_start 
/etc/rc.d/mdconfig: DEBUG: md2 config: -t vnode -f /mnt/VirtualDisk
/etc/rc.d/mdconfig: DEBUG: md2 type: vnode
/etc/rc.d/mdconfig: DEBUG: md2 dev: /dev/md2
/etc/rc.d/mdconfig: DEBUG: md2 file: /mnt/VirtualDisk
/etc/rc.d/mdconfig: DEBUG: md2 fs: /
/etc/rc.d/mdconfig: DEBUG: md2 newfs flags: 
Creating md2 device (vnode).
/etc/rc.d/mdconfig: DEBUG: checkyesno: background_fsck is set to YES.
fsck: Could not determine filesystem type
Fsck failed on /dev/md2, not mounting the filesystem.

FreeBSD [~]# mdconfig -lv
md0	swap	  512M
md1	vnode	 4096M	/var/swap
md2	vnode	 1024M	/mnt/VirtualDisk

FreeBSD [~]# mdconfig -du 2
But I'm unhappy about the script complaining about fsck and about the mount issue. Fact is, that I do not want to fsck neither mount it since it will be an iSCSI share. Still I could ignore this error since md2 is now listed by [cmd=]mdconfig -lv[/cmd] But then I tried rc.d/mdconfig2 and it doesn't seem to complain about fsck:
Code: 
FreeBSD [~]# /etc/rc.d/mdconfig2 start md2
/etc/rc.d/mdconfig2: DEBUG: run_rc_command: start_precmd: [ -n "${_mdconfig2_list}" ] 
/etc/rc.d/mdconfig2: DEBUG: load_kld: geom_md kernel module already loaded.
/etc/rc.d/mdconfig2: DEBUG: run_rc_command: doit: mdconfig2_start 
/etc/rc.d/mdconfig2: DEBUG: md2 config: -t vnode -f /mnt/VirtualDisk
/etc/rc.d/mdconfig2: DEBUG: md2 type: vnode
/etc/rc.d/mdconfig2: DEBUG: md2 dev: /dev/md2
/etc/rc.d/mdconfig2: DEBUG: md2 file: /mnt/VirtualDisk
/etc/rc.d/mdconfig2: DEBUG: md2 fs: /
/etc/rc.d/mdconfig2: DEBUG: md2 owner: 
/etc/rc.d/mdconfig2: DEBUG: md2 perms: 
/etc/rc.d/mdconfig2: DEBUG: md2 files: 
/etc/rc.d/mdconfig2: DEBUG: md2 populate cmd: 
/etc/rc.d/mdconfig2: DEBUG: checkyesno: _mounted is set to no.
But mdconfig -lv doesn't list it - so it's not configured?

So what am I doing wrong? My aim is to initialize a simple md device right at system boot in order to let eg. iSCSI (istg) benefit of the md device.

Any hints or ideas?
 
Have you tried changing the variable in rc.conf to mdconfig_md0 instead of mdconfig_md2?

I've no experience with the mdconfig startup script but I wouldn't be surprised if it runs in a loop, looking for 0 first, processing that, then 1, etc. The ifconfig scripts work like this for aliases. You'll probably find it's looking for mdconfig_md0, not finding it and giving up (unless you specify the md number as you say).

That may make /etc/rc.d/mdconfig start work but looking at the script I can't see any obvious way of stopping it trying to format and mount the device. You may end up having to make a custom rc script to run the commands on boot.
 
The following rc script should create the required md device on boot and remove it on shutdown (tested on 8.3-RELEASE). I'm not sure whether istg will be starting/stopping on boot/shutdown but if so the REQUIRE/KEYWORD stuff at the top may require tweaking to make sure istg starts after this and stops first.

(Note the device is hardcoded to /dev/md100)

Code: 
#!/bin/sh

# PROVIDE: iscsimd
# REQUIRE: LOGIN
# KEYWORD: shutdown

. /etc/rc.subr

name="iscsimd"
rcvar="iscsimd_enable"
start_cmd="iscsimd_start"
stop_cmd="iscsimd_stop"

disk="/mnt/VirtualDisk"
size="1G"

iscsimd_start()
{
        /usr/bin/truncate -s ${size} ${disk}
	/bin/chmod 0600 ${disk}
	/sbin/mdconfig -a -t vnode -f ${disk} -u 100
}

iscsimd_stop()
{
        /sbin/mdconfig -d -u 100
	/bin/unlink ${disk}
}

load_rc_config $name
run_rc_command "$1"

Save it as /usr/local/etc/rc.d/iscsimd, permissions 0500 and then add
Code: 
iscsimd_enable="YES"
to /etc/rc.conf.
It will then run on boot/shutdown and can be run manually as follows:

Code: 
# service iscsimd start
# service iscsimd stop
 
Here is a tuned version of previous rc script. The method of evaluating md[n] is limited to 100 only! Please let me know if someone knows a better way of getting the "n" of md_file_md[n]. I tried my luck in this thread: http://forums.freebsd.org/showthread.php?t=31707

rc.conf entries can look like:
Code: 
### Memory Disks
md_enable="YES"
md_file_md0="/mnt/VirtualDisk"
md_file_md1="/mnt/FileX"
md_file_md12="/mnt/SomeOtherFile"

The rc script for this would be:
Code: 
#!/bin/sh

# PROVIDE: md
# REQUIRE: localswap root
# BEFORE: SERVERS

. /etc/rc.subr

name="md"
rcvar="md_enable"
start_cmd="${name}_start"
stop_cmd="md_stop"
required_modules="geom_md:g_md"


md_start() {
    for i in $(seq 0 100); do

        unset MD_FILE
        eval MD_FILE=\$md_file_md${i}

        if [ ! -z $MD_FILE ]; then
            if [ -f $MD_FILE ]; then

                if [ ! -z "$(/sbin/mdconfig -lv | /usr/bin/grep "${MD_FILE}")" ]; then
                    USED_MD="$(/sbin/mdconfig -lv | /usr/bin/grep "${MD_FILE}" | awk '{print $1}')"
                    echo "mdconfig: Skipped md${i}. File $MD_FILE is configured as $USED_MD already."
                    unset USED_MD
                else
                    /sbin/mdconfig -a -t vnode -f $MD_FILE -u ${i} && \
                    MSG="mdconfig: Created /dev/md${i}" && \
                    SIZE=$(diskinfo -v /dev/md${i} | grep "mediasize in bytes" | grep -E -o "\(.*\)") && \
                    printf "%s %s %-10s %s\n" $MSG $SIZE
                fi

            else
                echo "mdconfig: Error: Skipped md${i}. File $MD_FILE not found."
            fi
        fi

    done
}

md_stop() {
    echo "Sorry - this script does not support \"stop\". Use i.e."
    echo "'mdconfig -du 3' in order to unconfigure /dev/md3"
}


load_rc_config $name
run_rc_command "$1"

Don't forget to [cmd=]chmod 0555 /usr/local/etc/rc.d/md[/cmd] the rc script. There is no stop since stop could cause collateral damage to data on md. There is also no file creation if a file doesn't exist. It is necessary to invoke i.e.
Code: 
truncate -s 1G /mnt/VirtualDisk
chmod 0600 /mnt/VirtualDisk
once before
Code: 
service md start
as mentioned earlier already.
 
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