An Experience of Orcball

Orcball is a team sword sport similar to a touch version of Rugby League except with padded weapons. I can only find references to it at Waikato University. The day I joined was a training session. I intend to publish a more technical article for those with a background in sword sports.

The people are friendly and welcoming. The emphasis seems firmly on having fun and improving skills. Players can borrow weapons from the Orcball club. You can see play videos online here.

As a new comer I was asked to use a single long-sword. This is a sensible safety rule until they figure out that I’m not going to bash through the opposition while ignoring all hits. That did make my life a bit difficult because I was up against people with sword and shield and long/short sword dual wielders. Apparently the game itself has rules that reduce dual wielding and shields.

The boffer swords are heavy compared to foam swords and even to sport-fencing weapons. They are made from PVC pipes padded by dense foam and wrapped in duct tape. The construction also has “thrust-safe” tips. They were still light enough to thrust single handed.

The weapons are heavy enough that a hard swing still inflicts damage. The rules require a gentle touch and no strikes to the head. These are sensible safety rules given that nobody wears protection. Afterall, this is meant to be a casual game that almost anybody can join. Valid target areas are: above the knees excluding the hands and head.

Mutual strikes in Orcball are termed “Irish” and do not count as a hit but there seems to be a wide interpretation of this rule. Irish includes mutual hits when the swings are simultaneous (even when the strikes are not) and therefore excludes counter-attacks.

The no-head-hit rule did get a bit frustrating. Opponents often left their heads open and I couldn’t strike! But this is Orcball and them’s are the rules and for good (safe) reasons.

I’m about average height but I happened to be taller than the opposing team. I switched to a finger grip where the index finger goes over the cross-guard and around the front of the blade. This made lowering the blade angle easier and increased point control. I wouldn’t have done that if the fingers/hands were valid targets.

It also takes a reasonable amount of fitness to play well. I’m not fit and sat out more than once to rest. Also, Orcball’s play on grass and tons of lateral movement meant I ruined my ankles. Oh well.

Verdict: would play again.


Ceph repair inconsistent pg placement groups

If you run Ceph for any length of time you may find some placement groups become inconsistent. The Ceph website has a handy list of placement groups statuses. The entry for "inconsistent" is what you'd expect; there's a difference between replicas of an object.

ceph pg dump | grep -i incons | cut -f 1 | while read i; do ceph pg repair ${i} ; done

(from here)

Get the cluster as healthy as you can before attempt this. Ideally the inconsistent placement groups should be at "active+clean+inconsistent". That means first resolving any missing OSDs and allowing them time to heal. If the OSDs don't seem to cooperate try restarting them and then retry the above command.

Explanation of the command:
ceph pg dump
gives a list of all pgs and their current status.
| grep -i incons
find only the lines containing "incons" - short for inconsistent
| cut -f 1
we only want the first field from the output
| while read i; do
loop through each line (one per pg), storing the pg number in a shell variable called i
ceph pg repair ${i}
instructs ceph to repair the pg
; done
signals the closing of the loop

The above command has always worked for me, but there are things you can try if this command doesn't work.

The ceph website says that inconsistent placement groups can happen as an error during scrubbing or if there are media errors. Check your other system logs to rule out media-errors because they may indicate a failing storage device.

Good luck!


Ceph on USB: Back to LVM.

Consider this a diary post. Perhaps the war-story is useful.

A further update on my Ceph cluster. I was running BTRFS v0.19 and the performance was horrible. This is most likely a very early version of BTRFS and I am running on very under spec hardware. While the future of BTRFS is bright, it is not for the nodes I have running now. I’ve reverted all my OSDs on USB keys back to XFS. That gave an instant 2-3 times speed up on writes.

I found a good deal on a second hand server with a generous case, 8 gigs of RAM, dual gig Ethernet ports and a decent enough CPU. It already has 3 spinning disks on-board and room for plenty more. I need to rearrange my office space to fit it in so that’ll take a couple of weeks.

I also have the budget to upgrade my desktop machine. The parts that come free after that upgrade will be built into another ceph node.

The other neat thing was creating an init.d script to automatically find and mount the lvm volumes, startup the OSDs then mount the Ceph filestystem. I needed something that performs this task quite late (read: last) in the boot process so that all the USB devices have had a chance to wake up.

So, once some work and deadlines are cleared then there'll be exciting things happening with my ceph cluster.