The Geek Diary

Archives for December 2020

How to set “max_report_luns” and “max_luns” on CentOS/RHEL 7 to scan more than 16,383 LUNs

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From CentOS/RHEL 7, the default value of parameter max_report_luns has been increased from 512 to 16383. Consequently, CentOS/RHEL 7.x can now discover more than 511 LUNs when the system scans the SCSI interconnect using the Report LUNs mechanism. Increasing this value beyond 16383 is generally not required. But if you want to increase it, then […]

How to Check the Size og yum Channels in CentOS/RHEL

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Question: How to find out how large a yum channel repository is, to know how much data the channel will sync to a local yum repository? To see the actual size of the repository use either the ‘yum repolist -v‘ or ‘yum repoinfo‘ command. Example for checking the size of “CentOS-8 – AppStream” yum channel […]

How to Check vendor of installed RPM packages in Linux

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This is a quick how-to post on checking the vendor of the installed rpms on a system. In some scenarios, a custom rpm package may not be compatible or supported on the specific system or environment. This post will help you identify the vendor of rpm which are either thrid party or not native to […]

TimeFinder SnapVX Concepts and SnapVX Operations

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TimeFinder SnapVX Overview TimeFinder SnapVX provides a highly efficient mechanism for taking periodic point-in-time copies of source data without the need for target devices. Target devices are required only for presenting the point-in-time data to another host. Sharing allocations between multiple snapshots makes it highly space-efficient. A write to the source volume will only require […]