Some of that reported unusable is actually usable. VxFS doesn't make many inodes in advance, it allocates & creates them as-needed. UFS, by contrast, creates inodes at a fixed ratio to storage, and the space those inodes consume truly is unusable.
But, if VxFS reports that space as free, then as people start to create files, VxFS start to make inodes, and support get complaints "Hey, I'm not able to use all the space you said was free, it doesn't behave like UFS did." So, VxFS makes a conservative estimate of how much space the inodes are likely to take up. If you make one single 150GB file, I believe you'll find the inode overhead is much smaller than the current estimate; if you make a billion zero-size files, then VxFS estimates of overhead will be too low. If you want to measure the log size separately, you can get that from the original mkfs command or it's echo; you can actually adjust the log size online, but it's a performance/overhead tradeoff. VxFS has generally been increasing the default log size on the belief that most customers will find that particular tradeoff beneficial, but you're free to experiment and change it. Regards, Scott > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of Prasanta Dash > Sent: Friday, August 10, 2007 11:22 AM > To: firstname.lastname@example.org > Subject: Re: [Veritas-vx] Vxfs space missing on new volumes > > Hello, > > > I just created 3 new volumes and cannot figure out why > there is so much > space missing when I do df -k on my > Solaris 8 server: > > /dev/vx/dsk/gemdg-san/gem5 > > 157227000 104776 147302092 1% > > I believe as a non root user you can use what is listed as available. > Difference > bewteen toal and used is avilable to superuser. This way > superuser can do some operations on the filesystem even after > it is reported as full. Also per my understanding once you > reach this point it will show you the actual available capacity. > > [EMAIL PROTECTED]:/ # vxassist -g local make test 10m > [EMAIL PROTECTED]:/ # mkfs -F vxfs /dev/vx/rdsk/local/test > version 7 layout > 20480 sectors, 10240 blocks of size 1024, log size 1024 blocks > largefiles supported > [EMAIL PROTECTED]:/ # mount -F vxfs > /dev/vx/dsk/local/test /mnt [EMAIL PROTECTED]:/ # df -k /mnt > Filesystem kbytes used avail capacity Mounted on > /dev/vx/dsk/local/test 10240 2141 7600 22% /mnt > [EMAIL PROTECTED]:/ # dd if=/dev/zero bs=4k count=2000 > of=/mnt/xyz > 2000+0 records in > 2000+0 records out > [EMAIL PROTECTED]:/ # df -k /mnt > Filesystem kbytes used avail capacity Mounted on > /dev/vx/dsk/local/test 10240 10141 99 100% /mnt > [EMAIL PROTECTED]:/ # l /mnt > > Notice that initially it reported u=2141, a=7600 t-(u+a)=500. > When I created a 8000 block file, now it u=10141 > (2141 metadata, > 8000 data), a=99 and u+a == t . > _______________________________________________ > Veritas-vx maillist - Veritasemail@example.com > http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx > _______________________________________________ Veritas-vx maillist - Veritasfirstname.lastname@example.org http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx