212 ©
Copyright 2017 QSAN Technology, Inc. All Right Reserved.
Maximum Disk Drive Quantity in an Auto Tiering Pool
256 (= 32 x 8)
Maximum Capacity of a Disk Group
64TB
Maximum Auto Tiering Pool Capacity per Pool
Maximum Auto Tiering Pool Capacity per System
256TB
1,024TB
By design, the auto tiering feature allows selecting policies that define how data are moved
between different tiers, and in many cases provides the ability to pin data to tiers
permanently or for specific periods of time.
Auto tiering storage is the assignment of different categories of data to different disk types.
It operates based on relocating the most active data up to the highest available tier and the
least active data down to the lowest tier. Auto tiering works based on an allocation unit
(granularity) of 1GB and relocates data by moving the entire unit to the appropriate tier,
depending on the tiering policy selected for that particular volume.
In order to ensure sufficient space in the higher tiers, 10% of the space is reserved in each
higher tier to prepare for the data allocation for those tiering policies which would allocate
initial space in highest available tiers. By reclaiming this 10% headroom, the least active
units within each tier move to lower tiers. The whole mechanism of auto tiering contains
three steps, statistic collection by accessed counts, ranking hotness data by the statistic
collection, and then relocation data via ranking.
11.2.2.
Hotness Analysis
The volume space is divided into units of equal size in which the hotness is collected and
analyzed per hour. This is also called sub LUN. The analysis consists of following two
phases:
Statistics Collection
Activity level of a sub LUN is determined by counting the quantity of read and write access
on the sub LUN. Logical volume manager maintains a cumulative I/O count and weights
each I/O by how recently it arrived. The new coming I/O is given a full weight. After
approximately 24 hours, the weight of this IO is nearly cut in half and continues to decrease.
The reduction weight is processing per hour by our precision algorism. This statistics
collection occurs continuously in the background for auto tiering pool.
Summary of Contents for XCubeSAN XS5224D
Page 71: ...SANOS User Interface 49 nnnnn RPM Power Supply Local PSU n status Reset to Default Yes No...
Page 99: ...System Settings 77 Figure 6 14 System Information...
Page 315: ...Monitoring 293 Figure 13 5 Hardware Monitoring...
Page 327: ...Support and Other Resources 305 Figure 15 1 Download Service Package in the SANOS UI...
Page 331: ...Support and Other Resources 309...