HP 504062-B21 Performance factors for HP ProLiant Serial Attached Storage (SAS - Page 4

SAS use for enterprise systems, to 20 percent higher Input/output Operations Per Second IOPS - on proliant dl360 g5

Get HP 504062-B21 - Dual Port 146 GB Hard Drive PDF manuals and user guides
UPC - 884420364795
View all HP 504062-B21 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 4 highlights

Another important factor to HDD performance is seek time, described as the time from when a read or write action is initiated until the data transfer from or to the disk actually begins. The smaller platters of SFF SAS drives inherently yield lower seek times, an advantage in file servers with frequent random accesses. SAS use for enterprise systems This section describes SAS design features that affect the performance and operating efficiency of SAS HDDs for enterprise-class systems. For a general discussion of SAS technology, refer to the HP white paper "Serial Attached SCSI Technology" available at the following HP web page: http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00302340/c00302340.pdf Since RAID strategies and AFR numbers favor high-density systems, SFF SAS drives are an attractive solution for large enterprise systems. Compared to 3.5-inch large form factor (LFF) SAS drives, 2.5-inch SFF SAS drives have these advantages: • Lower AFR • 15 to 20 percent higher Input/output Operations Per Second (IOPS) • 30 percent smaller physical size • Up to half the power consumption Increasing HDD density in a RAID-based system invariably enhances the overall performance of the storage system. Increasing the drive density also expands the choice of RAID strategies as indicated in Table 2. Table 2. Comparison of drive support in two 1U HP ProLiant servers Server DL320 G5 DL360 G5 Drive type LFF SAS [1] or SATA SFF SAS or SATA # of drives 4 6 RAID support RAID 0, 1 [1] RAID 0, 1, 10, 5, 6 [2] NOTES: [1] Requires optional SAS controller [2] RAID 6 requires P400i with 512MB Battery Backed Write Cache option At the drive level, smaller/faster is usually better. SFF drives offer a spindle-per-U advantage that yields better performance in most systems. Traditionally, LFF drives have a cost-per-GB advantage over SFF types. For workstation and small-tomedium business customers, getting the most storage capacity for the money is a key factor in setting up a system. For the enterprise IT architect, however, the goal should be to get the most work (that is, more IOPS) out of the system, and this is best achieved with high density storage systems. 4

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
Another important factor to HDD performance is seek time, described as the time from when a read or
write action is initiated until the data transfer from or to the disk actually begins. The smaller platters
of SFF SAS drives inherently yield lower seek times, an advantage in file servers with frequent random
accesses.
SAS use for enterprise systems
This section describes SAS design features that affect the performance and operating efficiency of
SAS HDDs for enterprise-class systems. For a general discussion of SAS technology, refer to the HP
white paper “Serial Attached SCSI Technology” available at the following HP web page:
Since RAID strategies and AFR numbers favor high-density systems, SFF SAS drives are an attractive
solution for large enterprise systems. Compared to 3.5-inch large form factor (LFF) SAS drives,
2.5-inch SFF SAS drives have these advantages:
•
Lower AFR
•
15 to 20 percent higher Input/output Operations Per Second (IOPS)
•
30 percent smaller physical size
•
Up to half the power consumption
Increasing HDD density in a RAID-based system invariably enhances the overall performance of the
storage system. Increasing the drive density also expands the choice of RAID strategies as indicated in
Table 2.
Table 2.
Comparison of drive support in two 1U HP ProLiant servers
Server
DL320 G5
DL360 G5
Drive type
LFF SAS [1] or SATA
SFF SAS or SATA
# of drives
4
6
RAID support
RAID 0, 1 [1]
RAID 0, 1, 10, 5, 6 [2]
NOTES:
[1] Requires optional SAS controller
[2] RAID 6 requires P400i with 512MB Battery Backed Write Cache option
At the drive level, smaller/faster is usually better. SFF drives offer a spindle-per-U advantage that
yields better performance in most systems.
Traditionally, LFF drives have a cost-per-GB advantage over SFF types. For workstation and small-to-
medium business customers, getting the most storage capacity for the money is a key factor in setting
up a system. For the enterprise IT architect, however, the goal should be to get the most work (that is,
more IOPS) out of the system, and this is best achieved with high density storage systems.
4