Chpt 18

Question 1

RAID 0

Answer 1

Stripping - uses 2 or more disks and improves performance, but does not provide fault tolerance

Question 2

RAID 1

Answer 2

Mirroring - uses two disks so if one fails, the system can continue to operate

Question 3

RAID 5

Answer 3

Stripped with parity - uses 3 or more disks with the equivalent of one disk holding parity information

Question 4

RAID 6

Answer 4

Functions similar to RAID 5, but stores parity info on two disks. Requires a minimum of 4 disks to implement

Question 5

RAID 10

Answer 5

RAID 1 + 0 - stripe of mirrors - configured as 2 or more mirrors with each mirror configured I. A striped configuration. Used at least 4 disks, and must be an even number

Question 6

Hot swapping

Answer 6

Replace failed disks without powering down the system (most hardware baes arrays support this)

Question 7

Jitter

Answer 7

The variation in latency between different packets

Question 8

3 techniques to restore a database backup

Answer 8

1) electronic vaulting - database backups are moved to a remote site using bulk transfers
2) remote journaling - database transfers occur more frequently, usually once every hour and only include the transaction logs since the previous transfer
3) remote mirroring - most expensive - a live database server is maintained at the backup site

Question 9

3 types of backups

Answer 9

• full - duplicate all files regardless of the archive bit
• incremental - stores files that have been modified since last full or incremental backup and changes the archive bit from 1 to 0
• differential - stores files that have been modified since last full backup and leaves the archive bit as 1 (will only require two restores - the full and the last differential)

Question 10

VTL

Answer 10

Virtual tape libraries - Enables disk-to-disk (D2D) backup by using software to make disk storage appear as tapes to backup software