Re: The old raw devices chestnut.

Jim Smith wrote: > Oracle: (my main experience) > At various times Oracle have claimed (talking to consultants, not > marketers) that raw devices are 5-20% faster than filesystems. This may > vary on the current state of the oracle code and/or the filesystem being > compared against. Veritas seem to agree by producing QuickIO for Oracle, > claiming "performance of raw with the management of filesystem". Well, I have been using the Veritas VxFS Quick I/O feature on Informix 7.31 and 9.20 for a couple of years now. On my system running on heavy OLTP load and large number of buffers, I get about 5x shorter checkpoint times on VxFS with QIO, compared to cooked chunks on 'plain' Veritas VxFS file system. And yes, LRU_MAX_DIRTY/LRU_MIN_DIRTY values are already at 1/0. QIO is essentially a normal file system which allows you to access the space reserved by a file through a character special device. So on Informix, you can use KAIO even on top of a file system. -- Toni