On a 1tb disk reducing reserved space from 5 to 2 saves almost 30 gb. Cutting the inodes down saves you some space but not nearly as much. Say 10 gb.
The differnce is once you format your disk you can't change the inode numbers. Tunefs can tune reserved blocks while the disk is mounted. I did reserved space with tunefs -m2 , Noatime then moved on. On 10/9/09, stephen mulcahy <[email protected]> wrote: > paul wrote: >> Check out the bottom of this page: >> >> http://wiki.apache.org/hadoop/DiskSetup > > Just re-reading that page, two suggestions that may not be appropriate, > > 1. Reducing reserved space to 0. AFAIK, ext3 needs a certain amount of > free space to function properly - the man page for mke2fs suggests that > this reserved space is used for defragmentation, as well as being > emergency space reserved for root. A quick Google doesn't turn up > anything more definitive, but setting it to 0 is a bad idea afaics. > > 2. Reducing the number of inodes. This is a good idea, if you are > really, really sure that nothing will create small files on that > partition. Unless you are absolutely certain of this, I would not change > from the default - I'm not clear on how much of an overall saving you'll > make and the downside to running to running out of inodes is that you > start getting "out of space" errors when you try to write to that disk > (despite df showing you loads of free space), so again, I'm not sure I'd > recommend this one. > > -stephen > > -- > Stephen Mulcahy, DI2, Digital Enterprise Research Institute, > NUI Galway, IDA Business Park, Lower Dangan, Galway, Ireland > http://di2.deri.ie http://webstar.deri.ie http://sindice.com >
