Re: Instance Initialization Problem

Been there, done that... Art is correct, offset the first chunk of each physical disk and your problem is solved. Terry Hillick VP, CSCSi "Thomas G. Smith" wrote: > Art, > > This is good scoop, but how did you know this? where is it documented? Most > Informix DBAs I know are wary of this problem, but overcompensate for it by > allocating too large an offset. Is there an authoratative source for this > info by OS/mfr/whatever? > > "Art S. Kagel" wrote: > > > Lloyd AJ Wilson wrote: > > > > > > Hello, > > > > > > We are currently working with Informix Online 7.12 UC1 and we are having > > > difficulties initializing our informix instance. Our servers run 128MB > > > memory on a dual Ultra Sparc UNIX 300MHZ processors with 3 18GB ultra > > > fast scsi hard drives. Each time we bring an instance online and then > > > back to off line we can no longer initialize our instance using the same > > > raw partition that the rootdbs was created on. > > [SNIP] > > > > There it is! You have stated the problem exactly. I assume the disk > > partitions are native Solaris/SunOS partitions and you are using them > > as RAW chunks. The problem is that Solaris writes the partition table > > entry for each disk partition onto the first 4K of each partition and > > NOWHERE ELSE! So if you created the Informix chunk with an offset of > > zero it overwrote the partition information of the first partition and > > when you next try to open the RAW file, by bringing the engine back up > > again, Solaris not only cannot find that partition but it will not be > > able to find any following partitions either. If you use native > > Solaris partitions you MUST use an offset of 4K for EVERY chunk (this > > will reduce the maximum size of a chunk from just under 2GB by an > > additional 4K but it cannot be helped). The only other option is to > > use a volume manager, like Veritas VM, which keeps its partitioning > > metadata in a section of the drive which is unavailable to the OS or > > Informix. > > > > (BTW you never see this problem when you create filesystems on Solaris > > because mkfs knows about the partition metadata and skips over it. > > Informix has no such knowledge.) > > > > Art S. Kagel