On 6/24/16 5:34 AM, Danny Shavit wrote: >> How do you determine allocated_size, with du? > yes via du >> How different? Can you show an example? > meta data file size= 5.6 GB (*6,089,374,208*) > > *df:* > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/dm-39 2725683200 955900860 1769782340 36% /export/v1 = 978,842,480,640 bytes > > *du:* du -s /export/v1/ > 952825644 /export/v1/ = 975,693,459,456 bytes > 978,842,480,640 -975,693,459,456 = > > Metadata size according to calculation=*3,149,021,184* bytes Oh, right. I should have thought of this; "du" counts some metadata as well, i.e. a directory full of zero-length files still consumes space which is reported by du. so your 975,693,459,456 bytes is file data as well as some metadata. -Eric > > Thanks, > Danny > > On Thu, Jun 23, 2016 at 9:12 PM, Eric Sandeen <sandeen@xxxxxxxxxxx <mailto:sandeen@xxxxxxxxxxx>> wrote: > > On 6/23/16 10:04 AM, Danny Shavit wrote: > > I see. We will try this direction. > > BTW: I thought that good estimate would be "volume_size - > > allocated_size - free_space". But it produced quite a difference > > compared to metadata dump size. > > Is there a specific reason? > > How do you determine allocated_size, with du? > > How different? Can you show an example? > > -Eric > > > Thanks, > > Danny > > > > On Thu, Jun 23, 2016 at 1:51 AM, Dave Chinner <david@xxxxxxxxxxxxx <mailto:david@xxxxxxxxxxxxx> <mailto:david@xxxxxxxxxxxxx <mailto:david@xxxxxxxxxxxxx>>> wrote: > > > > On Wed, Jun 22, 2016 at 06:58:16PM +0300, Danny Shavit wrote: > > > Hi, > > > > > > We are looking for a method to estimate the size of metadata overhead for a > > > given file system. > > > We would like to use this value as indicator for the amount of cache memory > > > a system for faster operation. > > > Are there any counters that are maintained in the on-disk data > > > structures like free space for examples? > > > > No. > > > > Right now, you'll need to take a metadump of the filesystem to > > measure it. The size of the dump file will be a close indication of > > the amount of metadata in the filesystem as it only contains > > the filesystem metadata. > > > > In future, querying the rmap will enable us to calculate it on the > > fly, (i.e. not requiring the filesystem to be snapshotted/taken off > > line to do a metadump). > > > > Cheers, > > > > Dave. > > -- > > Dave Chinner > > david@xxxxxxxxxxxxx <mailto:david@xxxxxxxxxxxxx> <mailto:david@xxxxxxxxxxxxx <mailto:david@xxxxxxxxxxxxx>> > > > > > > > > > > -- > > Regards, > > Danny > > > > > > _______________________________________________ > > xfs mailing list > > xfs@xxxxxxxxxxx <mailto:xfs@xxxxxxxxxxx> > > http://oss.sgi.com/mailman/listinfo/xfs > > > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx <mailto:xfs@xxxxxxxxxxx> > http://oss.sgi.com/mailman/listinfo/xfs > > > > > -- > Regards, > Danny _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
