Several Types of raw devices ? (or, block and char devices)
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi there all Informixers Most of the time when i install Informix on Unix i use raw devices such as /dev/rdiskname (on AIX, SCO) or /dev/rdsk/diskname (on Sun etc.). I recently came across an onld informix installation that uses the r-less disk for the raw device such that the raw devices are at /dev/diskname or /dev/dsk/diskname. I know that the r devices are charecter (crw-r-----) devices and that the none r are block devices (brw-r-----) but i want to know if there are any differences Informixwise as to the type of device it's using. - -- Nir Levy Email: nlevy@shaked.co.il System Administrator Phone: +972-3-5797551/5789536 Shaked Computer Systems Ltd. Fax: +972-3-5703705 http://www.shaked.co.il/~nlevy -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.1 for non-commercial use <http://www.pgp.com>; iQA/AwUBN95L0dBe37AVcjAxEQKacwCgxqre9DZ7dQF+TkDHDFO0bVjIXqQAoKa2 HoMr2DufwPuCE2L8NQOu4Orm =G1tf -----END PGP SIGNATURE-----
The block device is cooked and so slower since its I/O goes through the OS buffer cache. It is, BTW, the EXACT same physical disk space as the character device so if you are using soft links for chunk names just bring the engine down, relink the chunk names to the character devices and bring the engine backup. No sweat, no trouble, no danger, and instant 15-25% performance boost! Been there, done that. If you want to be double safe just archive before trying it. Art S. Kagel Nir Levy wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi there all Informixers > > Most of the time when i install Informix on Unix i use raw devices such as > /dev/rdiskname (on AIX, SCO) or /dev/rdsk/diskname (on Sun etc.). I > recently came across an onld informix installation that uses the r-less > disk for the raw device such that the raw devices are at /dev/diskname or > /dev/dsk/diskname. > > I know that the r devices are charecter (crw-r-----) devices and that the > none r are block devices (brw-r-----) but i want to know if there are any > differences Informixwise as to the type of device it's using. > > - -- > Nir Levy Email: nlevy@shaked.co.il > System Administrator Phone: +972-3-5797551/5789536 > Shaked Computer Systems Ltd. Fax: +972-3-5703705 > http://www.shaked.co.il/~nlevy > > -----BEGIN PGP SIGNATURE----- > Version: PGPfreeware 6.5.1 for non-commercial use <http://www.pgp.com>; > > iQA/AwUBN95L0dBe37AVcjAxEQKacwCgxqre9DZ7dQF+TkDHDFO0bVjIXqQAoKa2 > HoMr2DufwPuCE2L8NQOu4Orm > =G1tf > -----END PGP SIGNATURE-----