Redundant Gigabit Management NICs, Please

by Bob Plankers February 4, 2014 Dear Vendor

I’ve been doing a lot of system design work lately, building virtualization infrastructure for places where there is no pre-existing infrastructure available (also known as the revered “green field” deployment). One of the biggest issues I’ve had is that 10 Gbps switches can fall back to 1 Gbps when the proper transceiver is installed. However, […]

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Better Linux Disk Caching & Performance with vm.dirty_ratio & vm.dirty_background_ratio

by Bob Plankers December 22, 2013 Best Practices

This is post #16 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” In previous posts on vm.swappiness and using RAM disks we talked about how the memory on a Linux guest is used for the OS itself (the kernel, buffers, etc.), applications, […]

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Account for the Bandwidth-Delay Product with Larger Network Buffers

by Bob Plankers December 19, 2013 Best Practices

This is post #14 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” At times we can refer to certain network concepts with a “pipe” analogy, where bandwidth is the diameter of the pipe and latency is the length of the pipe. A […]

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Use a RAM Disk to Improve Disk Access Times

by Bob Plankers December 14, 2013 Best Practices

This is post #15 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” One of the biggest things folks in IT worry about is data loss. We go to enormous lengths to protect our data, using backups, snapshots, remote replication, rsync, scp, temporary […]

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Use Paravirtualized Devices On Your Virtual Machines

by Bob Plankers December 13, 2013 Best Practices

This is post #13 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” para- a prefix appearing in loanwords from Greek, most often attached to verbs and verbal derivatives, with the meanings “at or to one side of, beside, side by side” ( […]

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Do Not Collect System Performance Data From Guest OSes

by Bob Plankers December 12, 2013 Best Practices

This is post #12 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” Fans of the 12th Doctor Who have often heard the phrase “the Doctor lies.” The explanation for his lies is that, because he skips around in time, he knows things […]

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Adjust vm.swappiness to Avoid Unneeded Disk I/O

by Bob Plankers December 11, 2013 Best Practices

This is post #11 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” The Linux kernel has quite a number of tunable options in it. One of those is vm.swappiness, a parameter that helps guide the kernel in making decisions about memory. “vm” […]

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Zero Out Free Space

by Bob Plankers December 10, 2013 Best Practices

This is post #10 in my December 2013 series about Linux Virtual Machine Performance Tuning. For more, please see the tag “Linux VM Performance Tuning.” When we talked about the rationale behind storing logs centrally one big reason was thin-provisioned virtual disks. Those disks grow over time because filesystems on a virtual machine currently have […]

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