Re: Use of Veritas to create raw partitions?

"Chao Y. Din" <cdin@explorer.csc.com> writes: > Mike J Oropeza wrote: > > > > Tom Krotchko wrote: > > > > > > Using the Veritas logical volume manager, what is the correct procedure > > > to create raw paritions for use with Informix unde Solaris? > > > > > > It looks as if you just create a Volume containing a single Sub-Disk/Plex, > > > but I wondered if this was the best way, or were there some performance > > > considerations using this method? > > > > This works well, as I've used them with Oracle databases. The only > > problems I've encountered is that the device-special files' ownership is > > re-assigned to root when the system is rebooted. I added an rc script to > > chown them back to oracle. > > If you use veritas command, owner and group id will be set permanently. > The command is something like "vxedit ... owner=informix group=informix > mode=660 ..." > > Whether you want to have a single sub-disk/plex as a volume (or a raw > partition) depends on several factors. Our client demands raid5, we do > not have a choice but to configure raid5. If you don't have the > restriction as we do, there are two possible ways to accomplish better > performance: > > 1) a single volume (raw partition) consists of a single sub-disk/plex. > Use informix fragmentation to improve the performance. > > 2) a single volume consists of multiple sub-disk/plex (a stripe disk > array). In this case, do not use Informix fragmentation. > > My guess is: the first approach will outperform the second one. Any > comments? > > > > > One thing that surprised me is vxva's notion of a Megabyte, which Oracle > > and other programs often interpret as 1024x1024. Apparently vxva > > considers a Megabyte as 1024x1000. So, a 64M Oracle file won't fit into > > a 64M raw partition. Easily corrected if I used bytes instead of Mbytes > > when creating either structures. > > Good information. Along the samle lines - anybody has any input on using the volume manager provided disk striping and mirroring versus using using the volume manager to build logical volumes and then using the Informix fragmentation techniques for striping.Any comments on performance trade offs would be very helpfull. Thanks