Promise Technology VTRAK 15100, Руководство пользователя

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VTrak 15100 User Manual
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Cache Settings
There is a data cache on the VTrak controller and another one on each disk
drive. A cache holds data in volatile memory during RAID management and data
transfer activity. The right combination of cache settings for your needs can
improve VTrak’s efficiency and performance.
Disk Drive Write Cache – Activates the write caches on the disk drives.
Write Back Cache – Activates write-back feature of the caches for the disk
drives. A write back cache holds data after an I/O operation and tells the
controller the data has been written. The data is written as soon as the disk drive
is no longer busy.
This action speeds performance. If the power fails before the data is written to the
disk drive, the data will be lost. The alternative is a write-through cache, which
reports that the data has been written only after it actually has.
Automatic Flush Frequency – Specifies the flush frequency for VTrak’s
controller cache in seconds from 2 to 60. Zero means deactivated.
VTrak’s controller cache is equipped with a backup battery to power the cache
and save the data in it until regular power can be restored. Battery condition is
reported by WebPAM PRO and the CLU. See Chapters 4 and 5, respectively.
Where to Make Settings
In WebPAM PRO, these functions are under:
•
Logical Drive > Logical Drive functions
In the CLU, these functions are under:
•
Disk management > Disk operation > Enable/Disable disk write cache
• Logical Drive management > Modify Logical Drive parameters > Cache
policy
• Logical Drive management > Modify Logical Drive parameters > Flush
frequency