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Table of Contents
SVC Advanced Command Line
Easy Tier acceleration
The first setting is called Easy Tier acceleration. This setting is a system-wide one that is disabled by default. Turning on this setting makes Easy Tier move extents up to four times faster than when in the default setting. In accelerate mode, Easy Tier can move up to 48 GiB every 5 minutes, while in normal mode it moves up to 12 GiB. Enabling Easy Tier acceleration is advised only during periods of low system activity.
This setting can be changed online without affecting host or data availability. To turn on or off Easy Tier acceleration mode, run the following command:
SVC > chsystem -easytieracceleration <on/off>
Important: Do not leave accelerated mode on indefinitely. It is a best practice to run in accelerated mode only for a few days to weeks to enable Easy Tier to reach a steady state quickly. After the system is performing fewer migration operations, disable accelerated mode to ensure that Easy Tier does not affect system performance
SSH security
IBM recommends disabling the chacha20-poly1305@openssh.com cipher (Terrapin) by upgrading to one of the versions in “Remediation/Fixes” above and then running the commands below:
versions not affected (or higher) 8.4.0.14, 8.5.0.12, 8.6.0.4, 8.6.2.1, 8.6.3.0, 8.7.0.0
From the CLI
IBM_FlashSystem:V5100-01:superuser> chsecurity -sshprotocol 4
Using the GUI (8.6.0 and higher)
Settings > Security > Security Protocol Levels and choose SSH protocol level 4 in the GUI.
NPIV and zoning
Which WWN should I use to connect hosts to storage (check the host_io_permitted)
IBM_FlashSystem:V5100-01:superuser>lstargetportfc id WWPN WWNN port_id owning_node_id current_node_id nportid host_io_permitted virtualized protocol 1 50050xxxx0215A04 50050xxxx0005A04 1 1 000000 no no scsi 2 50050xxxx0255A04 50050xxxx0005A04 1 1 000000 yes yes scsi 3 50050xxxx0295A04 50050xxxx0005A04 1 1 000000 yes yes nvme 4 50050xxxx0225A04 50050xxxx0005A04 2 1 000000 no no scsi 5 50050xxxx0265A04 50050xxxx0005A04 2 1 000000 yes yes scsi 6 50050xxxx02A5A04 50050xxxx0005A04 2 1 000000 yes yes nvme
Remove a disk
Remove the 2 paths from disk
svctask chenclosureslot -exclude no -port 1 -slot 7 3 svctask chenclosureslot -exclude no -port 2 -slot 7 3
Then, you can mark fixed the errors present for the drives with:
svctask cheventlog -fix 2331 svctask cheventlog -fix 2337
Check now the drive status, it should reappear if not defect
lsdrive
Check also for bad blocks
IBM_Storwize:v5020:superuser>dumpallmdiskbadblocks
