HP A3550A User Manual - A3661-90001 - Page 84
RAID Performance
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Global Hot Spare RAID Performance Table 1-5 Relative Performance, Cost, and Availability Compared to an Individual Disk Physical disk configuration Relative read performance without caching Relative write performance without caching Relative cost per MB of storage Tolerance for single disk module failure? RAID-5 group with 5 Up to 5.0 Up to 1.25 1.25 Yes disk modules RAID-3 group with 5 Up to 4.0 Up to 4.0 1.25 Yes disk modules RAID-1/0 group with 10 Up to 10.0 Up to 5.0 2.0 Yes modules RAID-1/0 group with 6 Up to 6.0 Up to 3.0 2.0 Yes modules RAID-1 mirrored pair Up to 2.0 1.0 2.0 Yes 1-42 Planning Disk Unit Configurations
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1-42
Planning Disk Unit Configurations
Global Hot Spare
$´JOREDO´KRW´VSDUH´LV´UHFRPPHQGHG´LI»´LQ´5$,’¸¿»´5$,’¸¶»´5$,’¸±Ç¹»´RU´5$,’¸±´JURXSV»´KLJK´
DYDLODELOLW\´LV´VR´LPSRUWDQW´WKDW´GDWD´UHGXQGDQF\´QHHGV´WR´EH´UHJDLQHG´DV´VRRQ´DV´SRVVLEOH´DIWHU´D´
GLVN´PRGXOH´IDLOXUH´DQG´ZLWKRXW´V\VWHP´RSHUDWRU´LQWHUYHQWLRQµ´$´JOREDO´KRW´VSDUH´DOVR´LV´
UHFRPPHQGHG´WR´PLQLPL]H´WKH´GHJUDGHG´SHUIRUPDQFH´FDXVHG´E\´D´GLVN´PRGXOH´IDLOXUH´LQ´D´5$,’¸¿´
RU´5$,’¸¶´JURXSµ´
$´JOREDO´KRW´VSDUH´SURYLGHV´QR´UHJXODU´GDWD´VWRUDJH´EXW´HQKDQFHV´WKH´DYDLODELOLW\´RI´HDFK´5$,’¸¿»´
5$,’¸¶»´5$,’¸±Ç¹»´DQG´5$,’¸±´JURXS´LQ´D´GLVN´DUUD\µ
RAID Performance
7KH´5$,’´FRQILJXUDWLRQV´GLIIHU´LQ´WKHLU´SHUIRUPDQFH»´GDWD´DYDLODELOLW\»´DQG´GLVN´VSDFH´IHDWXUHVµ´
7DEOH´±¸¿´FRPSDUHV´WKH´UHODWLYH´UHDG´DQG´ZULWH´SHUIRUPDQFH´IRU´DUUD\´FRQILJXUDWLRQV´ZLWK´WKH´
SHUIRUPDQFH´RI´D´VLQJOH´VWDQG¸DORQH´GLVN´PRGXOH´ZKRVH´SHUIRUPDQFH´LV´±µ¹µ´7KH´UHDG´DQG´ZULWH´
SHUIRUPDQFH´VKRZQ´LV´WKH´WKHRUHWLFDO´PD[LPXP´SHUIRUPDQFH´UHODWLYH´WR´LQGLYLGXDO´GLVN´
SHUIRUPDQFHµ
²
7KH´SHUIRUPDQFH´QXPEHUV´LQ´WKLV´WDEOH´DUH´QRW´EDVHG´RQ´UHDGÇZULWH´FDFKLQJµ´:LWK´
FDFKLQJ»´WKH´SHUIRUPDQFH´QXPEHUV´IRU´5$,’¸¿´ZULWHV´LPSURYH´VLJQLILFDQWO\µ´5$,’¸¶´QXPEHUV´
DVVXPH´DOLJQPHQW´RQ´D´²¸.%´ERXQGDU\´IURP´WKH´VWDUW´RI´WKH´ORJLFDO´GLVNµ´3HUIRUPDQFH´PXOWLSOLHUV´
YDU\´ZLWK´WKH´ORDG´RQ´WKH´KRVW´V\VWHP´DQG´WKH´GLVN´DUUD\µ´´
Table 1-5
Relative Performance, Cost, and Availability Compared to an Individual Disk
Physical disk
configuration
Relative read
performance
without caching
Relative write
performance
without caching
Relative cost
per MB of
storage
Tolerance for
single disk
module failure?
RAID-5 group with 5
disk modules
Up to 5.0
Up to 1.25
1.25
Yes
RAID-3 group with 5
disk modules
Up to 4.0
Up to 4.0
1.25
Yes
RAID-1/0 group with 10
modules
Up to 10.0
Up to 5.0
2.0
Yes
RAID-1/0 group with 6
modules
Up to 6.0
Up to 3.0
2.0
Yes
RAID-1 mirrored pair
Up to 2.0
1.0
2.0
Yes