Posted May 11, 2010 22:37 UTC (Tue) by lbt (subscriber, #29672)
Parent article: MeeGo and Btrfs
FWIW I tried btrfs on a 1Gb mmc on a device running meego
I was using 2.6.33
I got disk full messages and yet df showed:
/dev/root 920M 651M 269M 71% /
So I went and asked about it ... some chat in #btrfs got me:
"I was told my fs was full. I just got a chance to do a du on it...585M"
"thats probably right"
"269m in use for metadata sounds correct"
"you will want to update your kernel to something 2.6.34 ish"
"OK, so btrfs is really not a good choice for small disks/devices not at ~50% overhead"
At the time I estimated 50% I wasn't clear on the metadata measurement bug in my kernel. I guess it's more like 25% used by metadata. I'd be interested to know if this is a percentage overhead or a lump-sum.
I'm really interested in many of the btrfs features - and on the desktop I may have volumes I'd make this tradeoff for in a hearbeat... not so sure about on my phone.