My kernel.log and debug log files had grown to over 2 GBytes each. This was due to log messages of this kind:
delay: estimated 0, actual 133
As another blog stated, this can be fixed by adding a parameter to the sound-usb-audio module of Alsa. So I did the same thing, creating a file /etc/modprobe.d/snd_usb_audio.conf with this content:
options snd-usb-audio nrpacks=1
After restarting Alsa or a reboot, the problems were gone, the logfiles kept small.
I strongly discourage the usage of rt2800 based WiFi dongles with the Raspberry Pi. For some weeks I have been debugging why my Raspberry Pi freezes and crashes all the time. And it turns out that it is the WiFi dongle. I was using an Edimax EW-7711UTn, but the chip is also being used in other devices. There seems to be a bug report for the Raspbian kernel, and I have spent quite some time on the Raspberry forum at Stackexchange. Currently, I hooked up the Raspberry Pi via Ethernet directly to my router. This works fine, but the router is upstairs, while the Raspberry is supposed to be downstairs, connected to my stereo. So this is only a stopgap measure until I have found a WiFi dongle that does not crash the Pi. Hints are welcome.
Update: I now switched to a TP-Link TL-WN725N with a RTL8188CUS chip. This adapter is much smaller (no external antenna) and surprisingly also quite a bit faster. I achieve ~1.9 MByte/sec sustained point to point datarates via SMB. So far no crashes or other problems. I will continue testing, but it looks much better than with the Ralink chip.
Update 2: Almost four months into testing the RTL8188CUS based WiFi dongle and it runs absolutely fine. I have uptimes of almost a month without any problems. After that the Pi degrades due to some of the daemons leaking or memory fragmentation. But I think this is bearable!