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Home -> Community -> Usenet -> c.d.o.server -> Re: [Q]: Raid 0 or Raid 5 for DATA tablespaces : Which is best ?
Jerome Grandjanny <grandjanny_at_ldg.bruyeres.cea.fr> wrote:
]I need to decide wether I use RAID 0 (stripping) or RAID 5 for
]the tablespaces containing the data and the indexes.
]
]The database must run 24/24-7/7.
]
]In some books about Oracle, I read that using RAID 5 is not always a
]good choice for data (possible performance problems during write
]operations).
Simple striping will not give you the uptime you need. You need some redundant disk to achieve that. Realistically this means you are looking at simple mirrors, striped mirrors, or RAID5.
Both forms of mirroring will provide faster writes than RAID5.
RAID5 uses less disk (more disk space per dollar).
RAID5 is plenty fast enough for our operations here. The example is from a 10 Gig Oracle 7.1 database running Mincom's MIMS app with 140 concurrent users, about 50 of them "active" at one time according to the TP system.
Redo log file system, (striped mirror)
OPERATIONS BLOCKS AVG TIME(ms) TYP NAME READ WRITE READ WRITE READ WRITE vol u09 21597 123347 830646 1236128 14.0 3.8 rollback file system, (striped mirror) OPERATIONS BLOCKS AVG TIME(ms) TYP NAME READ WRITE READ WRITE READ WRITE vol u10 29926 93743 400794 785344 17.5 9.3 Data file system (RAID 5) OPERATIONS BLOCKS AVG TIME(ms) TYP NAME READ WRITE READ WRITE READ WRITE vol u05 810136 307031 21472020 2912800 16.6 30.6
My thoughts when setting this up was to buy enough disks to mirror redo and rollback, but RAID5 the archive re-do logs and the data/indexes. I left contingencies in the work order to buy more disks if the RAID5 write performace penalty was too much.
I turned out that the RAID5 is fine in our case. This is on a Sun 1000e host with a SSA110 attached and running Veritas Volume Manager.
Regards,
George.
-- ,-,_|\ George Dau, / * \ Unix (Solaris, DEC Unix, Linux), NT, Oracle, Internet. \_,--\_/ Home: gedau_at_pobox.com Work: gedau_at_mim.com.au v WWW: http://pobox.com/~gedauReceived on Tue Aug 12 1997 - 00:00:00 CDT