IBM_Storwize:ITSOV5K:superuser> 

## System-wide settings 

The system-wide setting Easy Tier acceleration is disabled by default. Turning it on makes Easy Tier move extents up to four times faster than the default setting. In accelerate mode, Easy Tier can move up to 48 GiB per 5 minutes; whereas in normal mode it moves up to 12 GiB. The following are the two most probable use cases for acceleration: 

GLYPH<SM590000> When adding capacity to the pool, accelerating Easy Tier can quickly spread volumes onto the new MDisks. 

GLYPH<SM590000> Migrating the volumes between the storage pools when the target storage pool has more tiers than the source storage pool, so Easy Tier can quickly promote or demote extents in the target pool. 

Note:  Enabling Easy Tier acceleration is advised only during periods of low system activity only after migrations or storage reconfiguration occurs. It is recommended to keep Easy Tier acceleration mode off during normal system operation. 

This setting can be changed online, but only by using the CLI. To turn on or off Easy Tier acceleration mode, use the chsystem command and the lssystem  command to check its state, as shown in Example 9-5. 

## 9.1.3 Monitoring Easy Tier activity 

IBM_Storwize:ITSOV5K:superuser>lssystem |grep easy_tier easy_tier_acceleration off IBM_Storwize:ITSOV5K:superuser>chsystem -easytieracceleration on IBM_Storwize:ITSOV5K:superuser> 

When Easy Tier is active, it constantly monitors and records I/O activity and collects extent heat data. Heat data files are produced approximately once a day and summarizes the activity per volume since the prior heat data file was produced. 

The IBM Storage Tier Advisor Tool is a Windows console application that can analyze heat data files that are produced by Easy Tier. It also can produce a graphical display of the amount of “hot” data per volume and provide predictions about how more solid-state drive (T0) capacity, Enterprise Drive (T1), and Nearline Drive (T2) can benefit the system and storage pool performance. 

For more information about the IBM Storage Tier Advisor Tool, see this IBM Support web page. 

You can download the IBM Storage Tier Advisor Tool and install it on your Windows computer. The tool is included as an ISO file, which must be extracted to a temporary location. 

The tool installer is in temporary_location\IMAGES\STAT\Disk1\InstData\NoVM\ . Storage Tier Advisor Tool by default is installed in the C:\Program Files\IBM\STAT\ directory. 

On IBM Storwize V5000, the heat data files are found in the /dumps/easytier  directory on the configuration node, and are named dpa_heat.node_panel_name.time_stamp.data . Any heat data file is erased when it older than 7 days. 

