Re: Use of Veritas to create raw partitions?

Chao Y. Din wrote: > > 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. why use veritas at all for the raw disks? I'm using veritas and only use it for the filesystems that require it. I think having informix access the raw devices going thru veritas then solaris just is another layer which (I guess) slows it down. Does anybody agree (or disagree) with me?