Michael, vgcreate has an extent size option -S, which defaults to 4M. For a 1TB file, this must be at least 16M
Michael MacIsaac wrote: > I never got an answer to two issues regarding large logical volumes: > > > Did this issue ever get resolved: > > > > > I've experimented with vol group sizes from 1.4TB to 800GB. With the > > > less-than-1TB size, I experimented with vol group PE sizes from 8M to > > > 16M to 32M. > > > The vol group is 633600MB > > > PE size of 8M, I can only stripe logical vols under 100GB in size. > > > PE size of 16M, the largest logical vol with striping is 103GB (105600 > MB). > > > PE size of 32M, same as 16M PE, 103GB. > > > > I also recall an issue of mke2fs failing to make a file system of a > logical volume 1TB or larger. Was that ever resolved? > > On the first issue, I believe I have the answer which may be surprising. To > utilize all of the space of a striped volume group, the number of stripes > must be set equal to the number of phsical volumes. So for example. if you > want a 2TB striped LVM consisting of 98 3390-27s, you must use 98 stripes. > On the surface this may seem like too many stripes for good performance, > but perhaps the LVM code is smarter than that. Can anyone who knows the > LVM code comment? > > On the second issue, logical volumes larger than 1TB, the most DASD I can > seem to muster is in the tens of GBs range (just because IBM has gobs of > hardware doesn't mean everyone can own what they want :)), so I can't test. > Has anyone created a file system from a 1-2TB logical volume (2TB seems to > be the limit for Linux block devices)? ext3, reiserfs? > > Thanks. > > -Mike MacIsaac, IBM mikemac at us.ibm.com (845) 433-7061
