
396 14.2 Tuning Hardware Resources for Data Warehousing
every time a change is made to a file. RAID 1 can cause I/O bottle-
neck problems with respect to high usage areas of disk storage,
namely high usage database objects such as frequently written tables.
On the contrary, read access can be extremely fast, since some highly
sophisticated RAID arrays can read more than one mirror copy of a
file at the same time, allowing for parallel reads. RAID 1 is potentially
appropriate for sequential access for redo logs and index spaces in
OLTP databases and in data warehouses. RAID 1 is not appropriate
for random access of table rows from indexes using ROWID point- ...