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Archive for December, 2015

Stupid network issues

Why do all network cards work with Windows, but not with Linux or BSD? Well, whatever. I spent a lot of time this summer trying to get two Internet connections from the same Linux box for high availability. No luck, worked for a while and then failed. Just found out that the built-in network interface from Sundance shuts down under moderate load on Linux. That explains why it didn’t work.

Now I want to use the same box for a DMZ. We have a smart TV and I don’t trust it at all. It needs Internet access, but I won’t allow it anywhere near anything important. I don’t trust my phone (unfortunately) and I certainly won’t trust a TV!

Fortunately the Linux box has one free PCI-e slot, so this should be easy. Just install a new network card and go! Well, not quite. I hate VIA on Linux. I bought two network cards as the first failed to deliver, but the final solution was to add some boot options to grub: pci=nomsi,noaer.

There are still warnings about interrupts that nobody cares about (irqpoll might help, but increases power consumption), but for now it seems to work.

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Categories: Linux, Networking

Take care with BTRFS

I have long been an avid fan of ZFS, but though I have been running it on Linux for quite some time I’m not ready to trust it there. The upgrades can be painfull. No lost data so far, but several temporary outages with down time. Perhaps BTRFS is ready for prime time? In short no. It seems very promising, but Red Hat still has reservations. I have tested it with non-essential data. The basics are there and there are many cool features, but when I started to use some of them the file system suddenly turned read only. Why? Tried again, several times. Finally found it – old and fixed bug, but the fix is in the 4.x kernels. Way ahead of Red Hat/CentOS 7.
Of course, a read-only file system is much better than a corrupted one, so that was good. Even so I’ll wait a few more years before I trust anything vital to BTRFS, just in case. Having said that the long-term promise is there, so in five years I bet my servers will be running on BTRFS (unless the ZFS on Linux story changes)!

Categories: Linux