12 Mar

More FreeNAS Things

I once again bring you back to the lovely world of setting up FreeNAS. I now have Snapshots, SMART tests, and managed to track down and stamp out an annoyance in the logs. 

Setting up Snapshots turned out to be pretty easy, but not the most intuitive. We don’t make a whole lot of changes to the files stored on the NAS, but I wanted to be able to make use of the Previous Versions feature in Windows. Under the Storage tab, I set up a Periodic Snapshot Task to run every hour, every day of the week. and to keep each snapshot for two weeks. A little excessive, but it’s just for home use and space isn’t a concern right now.

Where I ran into a problem is that it offers a Begin time and an End time, but I don’t need a beginning and an end, I just want it to run every hour. It turns out that setting the begin and the end to the same time doesn’t give that effect, instead I had to set the start at midnight and the end 11 pm. It’s one of those things that I see now how they intended it to work, but it’s not how I thought it would. It also uses a completely different interface than the one for adding periodic SMART tests.

I’m a little paranoid about having a drive in here go bad. Even though I’ve never personally suffered from unrecoverable data loss, I’ve seen it happen enough times to other people that I’ve set this NAS up using RAIDZ2 so that I can lose two drives before everything goes bad. To make sure I catch a failing drive early enough, I’ve set up a a daily SMART test for all the drives along with a weekly long test. Setting up SMART test requires you to go to Tasks menu to start scheduling the tests. Amusingly, adding a Periodic Snapshot Task is not under the Tasks tab, but the Storage tab.

I thought the Snapshot scheduling interface was unintuitive, but the SMART tests interface really showed me what that meant. It tries to pack far too many options into its crammed window. I can select to run the tests every N amount of hours or on any number of specific hours throughout the day. I can have it run every N days or I can just go ahead and select any number of specific days. Then I’m given 12 checkboxes for month while the day and hour selections used either a slider or custom selection method. Finally, even if I want the tests to run every day, I can still prevent it from running on specific days if I wanted to. This causes my long test to have the following description:

Day of month Month Day of week
Everyday Every month Tuesday

It’s everyday as long as that day is a Tuesday. Granted, this is probably more a display issue than an actual concern, but it gave me a laugh.

The last thing I tackled was that I I kept getting errors that said:

kernel: arp: 10.0.1.20 moved from 00:17:f2:c3:de:22 to 28:cf:e9:7f:6e:c8 on igb0

And I realized that I knew what was at 10.0.1.20, but I had no clue which MAC address should have been at that address. To start solving this problem, I first threw together a spreadsheet with all the DHCP reservations, their host names, their IP addresses, and their MAC addresses for all our devices. Once I had that, I realized that the second MAC address was our Airport Express and the first was, correctly, our iTunes server and the day I fell down the Bonjour well came rushing back to me.

The Bonjour protocol allows certain low power always on devices to act as what’s known as a Bonjour Sleep Proxy. This allows other Bonjour enabled devices on the network to go to sleep so the Airport Express can pretend to be the device and, if it receives a request for a Bonjour service, will take that request and send a magic packet to wake up the sleeping device before handing the request to the now awake device.It’s actually not a bad implementation, but it causes FreeNAS to freak out any time the sleep proxy takes over. Thankfully, adding net.link.ether.inet.log_arp_movements=0 to /etc/syscntl.conf turns off the messages. Of course, if you’re getting these messages, make sure that Bonjour is the reason you’re getting them before disabling them.

With all of that taken care of, my next step is to get Birdy to start putting her files on it.

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