Questions tagged [performance]

Questions about server hardware and software performance, or network performance.

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Unexpected and unexplained slow (and unusual) memory performance with Xeon Skylake SMP

We've been testing a server using 2x Xeon Gold 6154 CPUs with a Supermicro X11DPH-I motherboard, and 96GB RAM, and found some very strange performance issues surrounding memory when compared to ...
Marc Micalizzi's user avatar
10 votes
1 answer
2k views

Troubleshooting Redmine (Bitnami Stack) performance

I've got a Redmine instance (Bitnami Stack) that's unusually slow. Because I'm just trying to get to the bottom of this, I have some theories which I'd like to discuss here. So, if anybody has any ...
arnekolja's user avatar
  • 201
8 votes
2 answers
1k views

what is the IOPS behavior when partitions of single disk are used in an LVM?

I have an ubuntu 14.04.1 LTS server which have LVM(backed by hardware RAID5) with logical volume and a volume group named "dbstore-lv" and "dbstore-vg" which have sdb1 sdb2 sdb3 created from same sdb ...
sherpaurgen's user avatar
8 votes
0 answers
4k views

Use perfmon to monitor a specific ASP.NET webapp across worker process restarts, IIS restarts, etc.?

I have a few perfmon performance counters that I'd like to track for a specific ASP.NET application over an extended period of time, say a week or a month. The trouble is that perfmon counters are ...
Chris's user avatar
  • 1,073
5 votes
0 answers
2k views

Streaming proxied responses with gzip on nginx

I have an nginx reverse proxy in front of a node.js backend server. In my node app, I am able to stream responses as they become ready, so that the client can start downloading resources referenced in ...
Dominic P's user avatar
  • 497
5 votes
0 answers
124 views

What could cause a LAMP server to perform poorer than my laptop?

I'm running a WEB application (PHP + MariaDB) for my company, developing on my laptop and running the production version on a dedicated server. Recently, I've started to measure performance and ...
François's user avatar
5 votes
0 answers
981 views

Disable NIC Receive Side Scaling hashing

On a benchmark lab system running Fedora Core 27 I've got Intel X710 10GE cards and 12-core Xeon processors, configured with 12 NIC queues and RX Flow Hashing based on both IP addresses and port ...
Alnitak's user avatar
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5 votes
1 answer
455 views

Server computational slowdown when RAM is used extensively

I have problem with server slowdowns in very specific scenario. The facts are: 1) I use computational application WRF (Weather Research and Forecast) 2) I use Dual Xeon E5-2620 v3 with 128GB RAM (...
Ivan Toman's user avatar
5 votes
0 answers
5k views

Why does chrome show a very long 'blocking' time (sometimes) when loading static files from Jetty 9

I'm seeing some strange behavior from Chrome when loading web resources from a Jetty 9.2.3 instance I'm setting up. In particular, I see some requests returning quickly, while others take a very long ...
Matt Sheppard's user avatar
4 votes
0 answers
1k views

Disk performance very slow on esxi 6

I have dedicated server with esxi6. I uploaded many iso from vsphere window client and i have 5 vms on it with 2 X1 TB HD SATA. The upload was quick but just now it is taking forever to upload. ...
Mr. Mirror's user avatar
4 votes
0 answers
1k views

Occasional excruciatingly slow resources transfer with Tomcat on AWS EC2

I have a running Tomcat v9 instance in a Docker container on an AWS EC2 host. It works perfectly, most of the time, and will once in a while deliver resources very slowly. What exactly is served ...
ccjmne's user avatar
  • 141
4 votes
0 answers
900 views

Prevent Gunicorn from loading slowly after an inactive period?

My Django project is running on gunicorn. Sometimes loading a page (and oracle procedures calls related) takes a lot of time. This occurs 90/100 when the server remains inactive for some minutes. How ...
Sam's user avatar
  • 151
4 votes
0 answers
4k views

Tuning mdadm RAID 5 performance?

I have a system with dual Intel E5-2620 v3 @ 2.40GHz, 64 GB ram, an LSI 3008 HBA, 8x 1.6 TB Intel S3510 SSDs. I've been playing benchmarking it in different configurations using fio and I've gotten ...
Evan's user avatar
  • 497
4 votes
1 answer
501 views

NGINX Worker Process, Burst Read Speed to only 1918kb/s

I am running an NGINX/1.8 server on Centos6.6 with multiple worker_processes, however while observing iotop I notice they burst up to 1918kb/s Read speed and rarely if at all pass that limit. I want ...
Kenneth's user avatar
  • 131
4 votes
1 answer
489 views

psping to localhost - improve throughput

I'm using following psping command to measure the bandwith throughput for localhost on a physical server psping -4 -b -l 8k -n 20000 localhost:1234 The throughput is around 150MB/s wich isn't all ...
Lieven Keersmaekers's user avatar
4 votes
0 answers
106 views

Windows Server 2003 terminal server extreme logon times

For the past week my users have been experiencing extreme logon times. They are generally in the 20 minute range or more. I will lay out my research below to see if anyone may know how to find the ...
Digital ink's user avatar
4 votes
0 answers
28k views

MySQL Workbench InnoDB Buffer Usage at 100%, always

The InnoDB Buffer Usage graph is always at 100%. I believe this started to happen when I changed MySQL's temp folder to a much bigger drive, does that make sense? I suppose the thing to do in this ...
GGGforce's user avatar
  • 759
4 votes
1 answer
525 views

Nginx + unicorn + spdy + performance testing

I have a ruby on rails website that is hosted on unicorn webserver behind a nginx reverse proxy. I want to evaluate if using spdy will enhance my performance under this setup. Specifically, I need ...
zango123's user avatar
  • 171
4 votes
0 answers
2k views

Why are pgpgin/s and majflt/s inconsistent in sar -B?

In sar -B ouptut, I would naively expect pgpgin/s to equal majflt/s multiplied by the system page size. From man sar: pgpgin/s Total number of kilobytes the system paged in ...
simonp's user avatar
  • 141
4 votes
0 answers
3k views

Amazon RDS: Sudden increase in Read IOPS and Throughput

I am using Amazon RDS to host the databases for my website. I am using the large instances for both my master and my read replica. Everything was running smoothly until suddenly the Read IOPS, Read ...
j0nes's user avatar
  • 955
4 votes
0 answers
2k views

How can I improve performance over SMB/CIFS for an application that has poor write speeds?

I have a third party application that reads several large files and generates a third large file. Its performance is quite good when the generated file is stored on "local storage", i.e. either a ...
Jeremy's user avatar
  • 661
4 votes
1 answer
1k views

BackupExec 12 + RALUS - VERY slow backups

We use Backup Exec 12 and the Remote Agent for Linux/Unix Servers (RALUS) to backup a large RHEL5 system. For various reasons we need to do a daily working set job. These working-set jobs run ...
LVDave's user avatar
  • 61
3 votes
0 answers
118 views

Reading from software RAID in parallel is slower than it "should" be, given other benchmarks

Note: I have seen some somewhat similar questions here, but: none of them concern reading many files in parallel, and most are 10+ years old and concern no-longer-relevant hardware and kernel ...
Daniel McLaury's user avatar
3 votes
2 answers
1k views

MySQL - Select queries 10x slower on Azure VM vs on-prem VM

We have been working on a project to migrate a MySQL database from an on-premise Linux server to a Windows VM on Azure (IaaS). (There's a specific reason because of which we have gone with the IaaS ...
Sridharan Srinivasan's user avatar
3 votes
0 answers
2k views

Gluster Performance

currently I try to setup a Gluster cluster and the performance is strange and I'm not sure, if I configured something wron. I'm using 4x Hetzner root server running Debian Buster with Intel i7, 128GB ...
TRW's user avatar
  • 518
3 votes
2 answers
1k views

Performance differences between EXT4 and XFS on kernel 4.15.0-76

OS: Ubuntu 18.04.4 LTS Kernel version: 4.15.0-76-generic Storage type: RAID10 (4 x SSD) Question: is it a bug for this version of kernel? EXT4 run a lot slower when we perform same SQL insert test; ...
Thomas G. Lau's user avatar
3 votes
0 answers
413 views

Why does Windows artificially throttle low priority processes during low overall utilization?

We have noticed that programs that run via Task Scheduler perform worse than when launched by the user. It seems others have noticed this too. It's apparently because by default, Task Scheduler runs ...
Sam Rueby's user avatar
  • 666
3 votes
0 answers
2k views

GeoIP vs IPset performance in iptables

I would like to ask you what is faster in term of performance GeoIP or IPset. Let me explain, imagine that I have rule: iptables -A INPUT -m geoip ! --src-cc US,UK,CA -j DROP And imagine that I ...
tomsk's user avatar
  • 297
3 votes
1 answer
1k views

Linux: how can I determine if an application is doing sequential or random disk I/O?

Everyone knows that databases tend to do lots of small random I/O while big data things like Kafka tend to do large sequential I/O, but if I'm approaching this as a sysadmin without making assumptions,...
Michael Martinez's user avatar
3 votes
0 answers
57 views

Do I need to create multiple filesystems on a virtual server to increase I/O performance?

I want to install Oracle on a virtual server. I don't really know the technology behind, my company just gave me a virtual server with multiple (virtual) disks. I have the possibility to divide those ...
Pierre's user avatar
  • 83
3 votes
0 answers
2k views

Determining Rails max threads and database pool size using Puma and NGINX

I noticed the default pool size for a Rails 5 App using Puma is equal to: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %> Which means that you can establish a max number of threads as an ...
Jorge Cuevas's user avatar
3 votes
0 answers
1k views

ZFS slow read speed on 8 drive 4 vdev striped mirrors

I have 8 3TB WD Red SATA drives sdb through sdi i use in my pool. My boot and OS drive is a an 850 EVO SSD on sda. The 8 WD drives are on a Supermicro AOC-SAS2LP-MV8 Add-on Card, 8-Channel SAS/SATA ...
CB40's user avatar
  • 31
3 votes
0 answers
248 views

Finding or estimating sequential vs random distribution of existing system (VMware / SAN)

IOMeter testing says the IOPs of the storage subsystem can range from hundreds of IOPs for 100% random loads to tens of thousands IOPs for 100% sequential loads. Is there any way I can measure or ...
TessellatingHeckler's user avatar
3 votes
0 answers
2k views

Spring Boot 1.2.7, Tomcat, CSS and Thymeleaf = Very Very slow service

I have a Spring Boot 1.2.7.RELEASE web application (with Tomcat embedded) which needs to handle a very high load spike, ~ 10k connections in 4 to 5 minutes on one server (there is actually a cluster ...
Jim Archer's user avatar
3 votes
0 answers
1k views

Performance counter to show real IIS response time

What performance counter should I use to display current average IIS response time? ASP.NET counters correctly show the time spent in ASP.NET, but real latency is much bigger, which is confirmed by ...
ovolko's user avatar
  • 131
3 votes
0 answers
2k views

Azure ASP.NET website http requests queued

We have a website deployed on Azure that has dreadful performance. When load increases, response times increase to whole minutes! CPU load is not even high, somewhere in the 40% region (we run one ...
Razzie's user avatar
  • 173
3 votes
0 answers
1k views

How to interpret atop Disk usage and what disk usage is reasonable

I have a a couple of virtual machines all with the same provider. I'm using them for web hosting and have started to get intermittent slow page load times. I've installed atop to try and get to the ...
Dom's user avatar
  • 37
3 votes
1 answer
2k views

On a system with 64GB mem the Linux Buffer run full while copying with dd to dev null and io stops till manual drop_caches

I am running a server with linux software raid 10. It is a dual CPU system with 64GB Ram. 2x16GB dimms related to each of the CPUs. I want to use dd to backup kvm virtual machines and run into a ...
user219392's user avatar
3 votes
0 answers
900 views

when and how to appropriately use /proc/sys/vm/drop_caches

You can clear page cache with /proc/sys/vm/drop_caches. Can someone provide a practical explanation of how this works, when as a sysadmin you would want to do this, how to determine if your system ...
Michael Martinez's user avatar
3 votes
1 answer
2k views

Maximum throughput on switch with different link speeds

While doing some benchmarking on a network app I discovered strange behavior that involves 100MBit and 1GBit ethernet clients connected through a switch (at-gs900/8e). I have one server (Gbit) and ...
Simon's user avatar
  • 31
3 votes
0 answers
490 views

iptable DNAT poor performance

I have the following rule for PORT FORWARDING: root@foo:~# iptables -t nat -S -P PREROUTING ACCEPT -P INPUT ACCEPT -P OUTPUT ACCEPT -P POSTROUTING ACCEPT -A PREROUTING -p udp -m udp --dport 1:1024 -...
VP.'s user avatar
  • 403
3 votes
1 answer
1k views

How to interpret increasing SHR reported by top?

The man page for top defines SHR as: t: SHR -- Shared Mem size (kb) The amount of shared memory used by a task. It simply reflects memory that could be potentially shared with other ...
MilesHampson's user avatar
3 votes
1 answer
2k views

Network behavior of slow Windows shared storage

I have got on my hands 3 Windows XP file servers (their sole purpose is their SMB share) running on a office with about 50 users. The workload is only office usage: they use it to store and share ...
lvella's user avatar
  • 324
3 votes
1 answer
654 views

Is WinSAT reliable to test the speed of my iSCSI, Fibre SAN, under bare metal or Virtualized?

I discovered the following command in this whitepaper: WinSat disk -read -ran -ransize 4096 -drive c Is it reliable to use against a SAN, or iSCSI drive? I would like to compare the output of ...
makerofthings7's user avatar
3 votes
1 answer
147 views

Software for performance testing

Is there a linux tool that acts like ab but for CLI, not HTTP. I want the one that can accept CLI command, number of runs, number of simultaneuously run instances and gives some stats as a result.
zerkms's user avatar
  • 461
3 votes
1 answer
147 views

Performance issue for webserver

We have asp.net sites based on dotnetnuke architecture and we are having two load balancing server with 2 gigs and with 24GB Ram. and SQL Server is with 48GB Ram. But still we are having some problem ...
Jalpesh Vadgama's user avatar
3 votes
1 answer
2k views

Tuning Linux TCP for large number of TIME_WAIT

It looks like we have a bunch of tcp connections hanging around on a busy webserver, this is the output from ss -s: Total: 366 (kernel 1037) TCP: 72108 (estab 130, closed 71964, orphaned 0, synrecv ...
Noodles's user avatar
  • 1,396
2 votes
0 answers
235 views

Apache creates ~3x as many threads as MaxRequestWorkers

I'm hosting a non-profit community wiki for the upcoming video game Baldur's Gate 3. Since it looks like the game is likely to have millions of players, we started worrying about server capacity. I'm ...
TaylanKammer's user avatar
2 votes
0 answers
1k views

Openstack: VM disk I/O Tunning

In OpenStack, I am facing I/O performance issues. I am using virtio-scsi driver support in the quest. Currently, I am getting below mentioned performance. WRITE: bw=37.2MiB/s (39.1MB/s), 37.2MiB/s-37....
gautam's user avatar
  • 21
2 votes
0 answers
797 views

Access disk io data in linux without tools like iotop/iostat to find processes or files with IO

We have regularly high load average. With the help of a zabbix agent, I could narrow it down to be mainly because of cpu iowait (and lastly disk io). I am not allowed to install any additional ...
nox's user avatar
  • 121

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