Simon Žekar – unix, communications, stupidities

gstat !! FreeBSD disk overview

Call me stupid but I accidentally found the gstat utility.

It gives you a super-cool overview of what your disks are doing.

Very useful in multiple disk ZFS…
was using iostat beforehand.

dT: 1.001s w: 1.000s
L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name
1 17 12 14 14.0 4 4 0.2 28.0| da0
1 17 12 22 14.8 4 4 0.2 26.7| da1
1 13 8 6 16.8 4 4 0.2 26.2| da2
1 17 12 22 11.9 4 4 0.2 20.3| da3
1 18 13 15 11.8 4 4 0.2 20.9| da4
1 18 13 15 12.0 4 4 0.2 21.8| da5
1 19 14 32 12.6 4 4 0.2 24.0| da6
1 24 17 31 12.2 5 4 0.2 138.3| da7
1 18 12 20 13.1 5 4 0.2 21.4| da8
1 15 9 18 15.0 5 4 0.2 25.1| da9
1 7 2 2 160.7 4 4 0.2 48.9| da10
1 16 10 21 12.3 5 4 0.2 19.6| da11
0 0 0 0 0.0 0 0 0.0 0.0| da12
0 0 0 0 0.0 0 0 0.0 0.0| da13
0 0 0 0 0.0 0 0 0.0 0.0| da14
0 0 0 0 0.0 0 0 0.0 0.0| da15
0 0 0 0 0.0 0 0 0.0 0.0| da16
0 0 0 0 0.0 0 0 0.0 0.0| da17
0 0 0 0 0.0 0 0 0.0 0.0| da18
0 0 0 0 0.0 0 0 0.0 0.0| da19
0 0 0 0 0.0 0 0 0.0 0.0| da20
0 0 0 0 0.0 0 0 0.0 0.0| da21
0 0 0 0 0.0 0 0 0.0 0.0| da22
0 0 0 0 0.0 0 0 0.0 0.0| da23
0 0 0 0 0.0 0 0 0.0 0.0| da24
0 0 0 0 0.0 0 0 0.0 0.0| da25
0 0 0 0 0.0 0 0 0.0 0.0| da26
0 0 0 0 0.0 0 0 0.0 0.0| da27
0 0 0 0 0.0 0 0 0.0 0.0| da28
0 0 0 0 0.0 0 0 0.0 0.0| da29
0 0 0 0 0.0 0 0 0.0 0.0| da30
0 0 0 0 0.0 0 0 0.0 0.0| da31
0 0 0 0 0.0 0 0 0.0 0.0| da32
0 0 0 0 0.0 0 0 0.0 0.0| da33
0 0 0 0 0.0 0 0 0.0 0.0| da34
0 0 0 0 0.0 0 0 0.0 0.0| da35
0 0 0 0 0.0 0 0 0.0 0.0| da36
0 0 0 0 0.0 0 0 0.0 0.0| da37
0 0 0 0 0.0 0 0 0.0 0.0| da38
0 0 0 0 0.0 0 0 0.0 0.0| cd0
0 0 0 0 0.0 0 0 0.0 0.0| da38p1
0 0 0 0 0.0 0 0 0.0 0.0| da38p2
0 0 0 0 0.0 0 0 0.0 0.0| da38p3
0 0 0 0 0.0 0 0 0.0 0.0| label/root
0 0 0 0 0.0 0 0 0.0 0.0| gptid/00e3191c-5b83-11e2-a6e9-00215acea494
0 0 0 0 0.0 0 0 0.0 0.0| label/rootfs
0 0 0 0 0.0 0 0 0.0 0.0| label/swap


FreeBSD disk labeling

I noticed that I’m a big user of my blog, simply because I forget things. So it is becoming “Note to self” blog 🙂

Recently I came to a stupid problem when the first controller in the server – the boot one – came numbered last on FreeBSD.

So the boot disk came to a /dev/da24.

The problem was that this server is changing the number of disk, so the boot device would always change, leaving a non bootable OS because of the /etc/fstab mount file.

So the tool for the action is Disk labeling: (old stuff)
FreeBSD disk labeling

Simply, boot into the single user mode and do a:
glabel label root /dev/da24a (root device or whatever is with you)
glabel label swap /dev/da24b (swap device number)

and change /etc/fstab devices to boot from /dev/label/root and /dev/label/swap for swap.

for example:
# cat /etc/fstab
# Device Mountpoint FStype Options Dump Pass#
/dev/label/root / ufs rw 1 1
/dev/label/swap none swap sw 0 0

FreeBSD view bandwidth and total bytes transferred for interface

Always installed nload on the server for which I wanted to view the bandwidth usage on.

But there’s preinstalled not-so-fancy-but-usable utility for FreeBSD:

systat -ifstat 1

S.

SSH bouncing update – getting rid of Killed by signal 1

If you read my article on ssh bouncing, you surely use it.

One annoying thing is “Killed by signal 1” when exiting the bounced session.

dolfi:~ simon$ ssh supercoolserver
Permission denied (publickey,keyboard-interactive).
Killed by signal 1.

So the solution is to change the ~/.ssh/config file and add the “2>/dev/null” to the very end of the ProxyCommand line.

Host hostalias
User root
ProxyCommand ssh bouncer.server -p 2222 'nc destination.server 2222' 2>/dev/null

Found the solution here. Thanks to merdely.

S.

FreeBSD disk/partition resize – grow on version 8.2 and newer under vmware vSphere / ESXi

This one is easier than previous (FreeBSD 7.x or older).

It may be possible to do it all live but you need to find a way for FreeBSD to see the growed disk size.

• Shut down the server
• Grow the disk size
• Boot FreeBSD in single user mode (number 4 at boot)

gpart show

sysctl kern.geom.debugflags=16

gpart resize -i 1 da0

gpart resize -i 6 da0s1

growfs /dev/da0s1f

Reboot for a clean feeling and you’re done.

S.

FreeBSD disk/partition resize – grow on version 7.x or older under vmware ESXi

I’ve tried this on vmware ESXi4.1.

First, shut down the server and enlarge the disk size in the VM config.

Boot into single user mode (press 4 and boot).

Check the block count of the new disk (seen at boot – dmesg) – in our case 419430400.

Update the partition size with fdisk -u /dev/da0

when asked, the start of the updated partition stays the default but the end of the partition you can write the block count of the new disk (419430400). Actual end is less that this size, but fdisk sees that and it suggests the correct number which you can agree on.

you can check if all went well with fdisk -s. It should be the new block size (little less that the block cound of the disk) – write down this number.

time to update the slice table. This is done by:

bsdlabel -e da0s1

There you edit the number under “# “raw” part, don’t edit”. Funny 🙂 You must change the number here to the block count seen with “fdisk -s” after updating partition.

And then change last line – usually entry “f” which is by default “/usr”. Remember that you can only grow the last partition !!.

Change the first number of the “f” entry with the number which is number of blocks seen via “fdisk -s” minus the offset of the f entry (next number in line).

Save this config.

Now the partition is bigger but the filesystem doesn’t know about it. This is where growfs comes in (was surprised to see that it has been introduced in BSD 3.x).

growfs /dev/da0s1f

and there, you have resized partition.

type CTRL+D to boot into the new – grown partition.

I noticed that this procedure works only for version smaller than FreeBSD 8.
It should work on higher versions but I’ve seen very unstable behaviour – kernel crashes… after using fdisk/diskabel.

For versions FreeBSD 8+ the utility gpart (don’t confuse with gparted !!!t) is used which will be described in next post.

shell output history in screen(1)

We all know the great things screen can do for a sysadmin – you can detach running process and come back to see it anytime.

But if you want to see what was happening while you were gone, you need to browse the history of the shell process.

It’s simple, CTRL+A [. That means CTRL+A to enter command mode, then release it and press character “[“.

More in detail here.

syncing FreeBSD server with NTP is simpler than you may think

After setting up a config file for the NTP on every server, i figured out that a stock settings just work.

so adding:

ntpd_enable="YES"
ntpdate_enable="YES"

to the /etc/rc.conf just does the trick (and starting services if not rebooting the server).

After some moments of running the ntp client you can check it with:

# ntpq -c peers
remote refid st t when poll reach delay offset jitter
==============================================================================
*ntp2.Housing.Be 128.32.206.55 2 u 16 64 377 189.371 -14.785 5.513
mighty.poclabs. 169.229.70.64 3 u 28 64 377 132.913 -14.411 5.034
+vps1.cobryce.co 64.235.98.66 3 u 16 64 377 180.600 -22.410 5.258

where servers marked with * are the selected server and + are the candidates for ntp sync.

blocking certain MAC addresses from joining your Cisco AP

In hope for an energy to revive this blog, a quick post.

If you need to block an abuser flood-trying to connect to your AP, resulting in multiple radius connections and error messages, you can make ACL on AP like this:

# access-list 760 deny 0002.725f.93c3 0000.0000.0000
# dot11 association mac-list 760


where 0002.725f.93c3 is the abusers mac address.

Happy banning,
S.

FreeBSD and shared iLo 2 port on HP servers

In order for HP iLo 2 management interface to continue working on a shared ethernet port after FreeBSD kernel loads the bge drivers, you must add following line to /boot/loader.conf

hw.bge.allow_asf="1"

And reboot.

Hope it will save you some minutes figuring it out…

S.