1 min read
0
The return of misaligned IO
We have started seeing misaligned partitions on Linux guests runnning certain HDFS distributions. How these partitions became mis-aligned is a…
Latest Posts
1 min read
0
High Response time and low throughput in vCenter performance charts.
Often we are presented with a vCenter screenshot, and an observation that there are “high latency spikes”. In the example, the response…
1 min read
0
Creating compressible data with fio.
Today I used fio to create some compressible data to test on my Nutanix nodes. I ended up using the…
1 min read
0
Code Red – The healthcare.gov story.
A downtime classic, for several months in 2013 the troubles of a very particular website were front page news across…
3 min read
0
Cache behavior – How long will it take to fill my cache?
When benchmarking filesystems or storage, we need to understand the caching effects. Most often this involves filling the cache and…
2 min read
0
SQL*Server on Nutanix. Force backups to HDD.
As an experiment, I wanted to (a) Create a HDD only container, and (b) measure the bandwidth I could achieve…
2 min read
0
Things to know when using vdbench.
Recently I found that vdbench was not giving me the amount of outstanding IO that I had intended to configure…
4 min read
0
SATA on Nutanix. Some experimental data.
The question of why Nutanix uses SATA drive comes up sometimes, especially from customers who have experienced very poor performance using…
2 min read
0
Impact of Paravirtual SCSI driver VS LSI Emulation with Data.
TL;DR Comparison of Paravirtual SCSI Vs Emulated SCSI in with measurements. PVSCSI gives measurably better response times at high load. …
3 min read
3
SuperScalin’: How I learned to stop worrying and love SQL Server on Nutanix.
TL;DR It’s pretty easy to get 1M SQL TPM running a TPC-C like workload on a single Nutanix node. Use…
2 min read
0
Lord Kelvin Vs the IO blender
One of the characteristics of a successful storage system for virtualized environments is that it must handle the IO blender. Put…
3 min read
0
Multiple devices/jobs in fio
If your underlying filesystem/devices have different response times (e.g. some devices are cached – or are on SSD) and others…
2 min read
0
Here be Zeroes
Many storage devices/filesystems treat blocks containing nothing but zeros in a special way, often short-circuiting reads from the back-end. This…
1 min read
0
Designing a scaleout storage platform.
I was speaking to one of our developers the other day, and he pointed me to the following paper: SEDA:…