2 min read
0
Back to basics – gprof PT1 (generating a profile)
A while ago at work we were discussing the pros and cons of the classic Linux profiler gprof… What are…
Latest Posts
2 min read
0
Notes on tuning postgres for cpu and memory benchmarking
Recently I wanted to measure the impact of NUMA placement and Hugepages on the performance of postgres running in a…
1 min read
0
Effect of POSIX_FADV_SEQUENTIAL and POSIX_FADV_RANDOM on IO performance.
Previously we looked at how the POSIX_FADVISE_DONTNEED hint influences the Linux page cache when doing IO via a filesystem. Here…
1 min read
0
Using fio to read from Linux buffer-cache
Sometimes we want to read from the Linux cache rather than the underlying device using fio. There are couple of…
1 min read
0
Understanding QEMU devices
Not sure where I came across this, but it is an excellent description of QEMU (and virtualization in general). I…
1 min read
1
Using Prometheus and Grafana to monitor a Nutanix Cluster.
Using a small python script we can liberate data from the “Analysis” page of prism element and send it to…
1 min read
0
A Nutanix / Prometheus exporter in bash
Overview For a fun afternoon project, how about a retro prometheus exporter using Apache/nginx, cgi-bin and bash!? About prometheus format…
1 min read
0
Linux memory monitoring (allocations Vs usage)
How to use some of Linux’s standard tools and how different types of memory usage shows up. Examples of using…
1 min read
2
Using iperf multi-stream may not work as expected
Running iperf with parallel threads TL;DR – When running iperf with parallel threads/workers the -P option must be specified after…
1 min read
0
mpstat has an option to show utilization per NUMA node
Not sure how long this has been a thing, but I recently discovered that mpstat takes a -N option for…
1 min read
0
Running the ML-Perf Storage benchmark on Nutanix files.
Some technical notes on our submission to the benchmark committee. Background For the past few months engineers from Nutanix have…
1 min read
0
Viewing Nutanix cluster metrics in prometheus/grafana
Using Nutanix API with prometheus push-gateway. Many customers would like to view their cluster metrics alongside existing performance data using…
1 min read
0
Effects of CPU topology on sqlserver guests with AHV.
VM CPU Topology The topology (layout) that AHV presents virtual Sockets/CPU to the guest operating system will usually be different…
1 min read
0
fio versions < 3.3 may show inflated random write performance
TL;DR If your storage system implements inline compression, performance results with small IO size random writes with time_based and runtime…
1 min read
1
Specifying Drive letters with fio for Windows.
fio on Windows Download pre-compiled fio binary for Windows Example fio windows file, single drive This will create a 1GB…
1 min read
0
Hunting for bandwidth on a consumer NVMe drive
The Samsung SSD 970 EVO 500GB claims a sequential read bandwidth of 3400 MB/s this is a story of trying…
1 min read
0
Database sizes for HammerDB TPC-C/ SQLserver
The on disk size for small DB sizes. Taken from SQLserver properties immediately after creating the TPC-C like schema in…
1 min read
0
1 min read
0
Generate load on Microsoft SQLserver Windows from HammerDB on Linux
Often it’s nice to be able to drive Windows applications and databases from Linux, especially if you are more comfortable…
1 min read
0
QCOW 3 Ways
How to mount QCOW images as Linux block devices tl;dr guestmount (requires libguestfs-tools) sudo guestmount -d <vm-name> --ro -i <mountpoint>…