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Questions tagged [optimization]

Optimization is the process of modifying a system to make some aspect of it work more efficiently or use fewer resources.

2
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1answer
33 views
+50

Debugging and fine-tuning the linux process scheduler

When debugging sporadic web application slowdowns, I've found that all the processes have quite high maximum scheduling delay. # perf sched record -- sleep 10 && perf sched latency --sort max ...
0
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1answer
26 views

How to convert swap partition from RAID1 to RAID0 using mdadm

How to convert linux SWAP memory from RAID1 to RAID0? Start with:2 exact size swap formatted partitions (/dev/sdc5 and /dev/sdd5) on 2 physically separate disks that are used via Software RAID(named ...
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4answers
372 views

Joins performed without indexes: 5568

I was trying to do mysql optimization. Yesterday the CPU usage was 100%. I am trying to optimize with mysqltuner but this time I gave a mysqltuner warning. I have a high-traffic db. 500-600 ...
9
votes
1answer
133 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 ...
0
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0answers
36 views

Slow transfer rates on ubuntu server

OS: Ubuntu 16.04 I have dedicated server with symmetric bandwidth of 100 Mbps. However, every server process I run tops out at 20 Mbps in either direction. I have tested this on 25 MB ~ 500 MB files ...
0
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0answers
468 views

CloudFront HTTP/2 slower (high TTFB) than HTTP/1.1

My site was running on HTTP/1.1 with CloudFront at front, Webpagetest reports the load time usually at 2 seconds. Yesterday I enabled HTTP/2 (and SSL) on CloudFront, expecting to see an improvement. ...
0
votes
1answer
21 views

Which parameters and setting affect network throughput when connecting two machines together without a switch?

I have a situation where I need best possible throughput (TCP/IP sockets & SMB3) between two Windows Server 2016 connect with a 1m patch cable. I have to use existing hardware. When you connect ...
1
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2answers
537 views

mysqld taking 800% CPU since traffic increased on my site, how to fix

i have centos 7 x64 64 GB RAM and 500 GB of SSD dedicated server., And recently cpu usage was really high, $ uptime 13:50:30 up 169 days, 1:53, 1 user, load average: 37.48, 37.64, 33.60 so i ...
0
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0answers
38 views

Performance issues with NUMA enabled processors

I have an image processing algorithm which was initially implemented in plain C++. I changed the implementation to use AVX/SSE instructions (based on the instruction set supported by processor) and I ...
0
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0answers
123 views

Should I worry about TTFB?

I have read differing opinions on the subject, but Im also wondering how much of this is affected by server location. I have a VPS in NY, USA and im an Australian developer, VPS' are pretty pricey ...
8
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6answers
3k views

At what point is a server considered idle?

Conceptually, what is the definition of an idle server? What resource metrics would you look at to make an assumption on whether or not a server was idle? Would you look at: CPU utilization Disk ...
0
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0answers
71 views

Optimizing nginx with SSL for bot traffic without sessions

The service I run, cronitor.io, has a telemetry collection API that sees bursts of traffic around 1000rps. (overall baseline is much lower, call it 100rps) Most of our requests come from things like ...
0
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0answers
97 views

CDN for multiple domains with mod_pagespeed (Apache)

I have a vps server with multiple sites and I have a cdn that is accessible by: example.gocache.com All of these sites are enabled to use this CDN however, I wanted mod_pagespeed to automatically ...
1
vote
1answer
665 views

How to speed up connection with a server in China

I have a EC2 server in China using Amazon AWS China. It's a server with : Apache 2 and PHP The database is a RDS instance running MySQL (also in china) The problem: Access from out of China is very ...
0
votes
1answer
90 views

How to simplify my nginx reverse proxy config

I have finally gotten around to setting up a Nginx reverse proxy to handle the multiple websites I host at my house since I only have one external IP address and everything is working, but what I want ...
2
votes
2answers
254 views

winbind authentication through apache slow

I have a linux machine setup to authenticate users using Active Directory with samba/winbind. Apache is then setup to use that to authenticate the users. This is done using: <IfModule ...
3
votes
1answer
106 views

Speed up backup of just ACLs on large file systems

I'm trying to make quick backups of just the ACLs on large GNU/Linux file systems. Extended permissions are not really necessary. I run 4 little benchmarks on a small partition just to make an ...
1
vote
2answers
103 views

Minimal upgrade from one minor CentOS version to the next

I would like to update our remote systems from CentOS 7.2 to 7.3. Is there an option that would only install the minimum number of packages required? The standard upgrade would involve downloading ...
1
vote
1answer
144 views

Should a KVM host be doing things other than hosting VMs? (such as ZFS)?

What are the performance and stability implications of running resource intensive services in a hypervisor vs guest OS? I want to set up a workstation with both Linux and Windows, hosted by (probably)...
0
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0answers
28 views

Optimize webserver to handle huge load spikes [duplicate]

Our application is growing fast so now we need to scale the infrastructure to don't slow down the entire website without worrying on how many users we have The backend system is based on many curl ...
1
vote
1answer
389 views

Tune when sssd goes into offline mode

I have a linux server with sssd using an ldap server for the auth backend. The connection to the ldap server is flakey, so I get authentications which are fine and then suddenly one will take forever ...
-2
votes
2answers
94 views

Server bandwidth is going crazy, after reboot all ok

I have a streaming server with 10gbps card on it. I'm using ~2.5gbps. My server is running perfect for 8-9 hours / day, and after that is going crazy, and everyone is freezing. At exactly the same ...
3
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0answers
1k views

`nginx reload` and `nginx -t` very slow - how to investigate

I have a quite small VPS on AWS (EC2 t2.nano) that is running an nginx server. while sometimes a sudo service nginx reload or nginx -t is blazing fast, most of the time it is horribly slow (>60 ...
4
votes
2answers
3k views

LVM cache in writeback mode is equivalent to external ext4 journal?

I am running ext4 filesystems on LVM. The two big speedup options I'm looking at are, LVM cache and the external ext4 journal. It sounds like if I'm using a single SSD for this, LVM cache in ...
0
votes
2answers
392 views

nginx multiple paths (too many)

i got this working nginx config: server { listen 80; server_name mydomain.com; root /var/www/mydomain/wordpress; index index.html index.php; location /customer1 { alias /var/www/...
0
votes
1answer
415 views

NGINX + PHP-FPM multidomain optimization

I am trying to optimize the parameters of PHP-FPM on a VPS with multiple domains. Each domain is configured with its own user/group, NGINX uses different PHP-FPM sockets. For each domain I have ...
1
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0answers
99 views

To which value set ulimit

I'm setting up nginx from what I've understood the worker_connections value must not exceed the maximum number of open file descriptors retruned by ulimit -n. On my fresh 16.04 ubuntu installation ...
0
votes
1answer
1k views

nginx: configuration file test failed [closed]

I using DirectAdmin and Nginx installed, i have huge clients at the moment and i see "Nginx 503 Error" sometimes, and i have 3Gb ram with 790 used ram... And now i want increase Worker Connections, ...
2
votes
1answer
191 views

Move htaccess rules to apache configuration files

I'm running a website with Joomla on a dedicated server (Debian), and i've read that moving .htaccess rules to apache2 configuration files may result in a good performance improvement (Apache HTTP ...
-2
votes
1answer
104 views

How to choose database and backend server locations?

I could not find a tutorial for beginners for how to locate my servers. For instance I use Compose.io for my MongoDB and DigitalOcean for my Meteor.js app. Lets say I want to have fast service in ...
4
votes
0answers
623 views

Identifying bottleneck with nginx VPS load testing

I'm trying to optimize a Digital Ocean droplet (512mb), testing using loader.io I'm testing on my homepage, which is HTTPS / PHP. I setup FastCGI page cache, which got me from 100 req/sec to 2,000 ...
0
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0answers
26 views

Way to know what source is reading the most from MySQL Server(RDS)?

I have a mysql server which is registering very large bandwidth usage. I want to know what options I have for: Knowing what source is using the MySQL server most. (server ip?) What tables or queries ...
1
vote
2answers
274 views

Track what is causing AWS RDS to use insanely high bandwidth

We are having a high traffic (100K hit/day) Drupal news website hosted on AWS. Its behind cloudflare & 2 Load Balanced Varnish servers. For some reason the bandwidth usage is very high for RDS. ...
-4
votes
1answer
93 views

My website is superslow but the %CPU is only 25%

I have 2 servers for my website : One server 256GO RAM 20c/40t for MySQL One server 256GO RAM 20c/40t for Apache The MySQL server is always ok (30-50% of CPU is used). But the Apache ...
1
vote
1answer
154 views

Ubuntu LAMP server busy at peak hours

I'm running a Ubuntu 14 server with LAMP on virtual cloud hosting (CityCloud). The server is usually doing very well with response time<0.5s. However, the problems start at peak hours, mainly ...
0
votes
1answer
1k views

nginx time to first byte

I running several project on one machine, below with all the info. on nginx config if PHP project use fastcgi cache, Node.js project use proxy_pass , and all project use gzip. I'm new to maintain ...
0
votes
3answers
512 views

Hyper-V failover cluster auto load balancing

We have a 2 unit Hyper-V cluster and I was wondering if there is a way to auto load balance the two? If one unit is restarted then I need to manually reassign some of the VMs to the unused hypervisor, ...
0
votes
0answers
24 views

Go server response times

I just started playing around with a hosted VPS (running Ubuntu). I let it run the simplest Go server that listens to port 8080 and returns "hello world" on path /hello. Then I started sending ...
0
votes
1answer
516 views

How to allocate more resources to Node.JS process?

I'm not a (very good) back-end developer so understanding processes and memory are a little about my pay grade. I'm currently building an app using the MEAN stack. I have a separate Express server ...
0
votes
0answers
12 views

ExpressJS + MongoDB: Better to make one API call with 10,000 objects, or 10,000 individual API calls? [duplicate]

I'm building an app that relies on a web scraper built in Node/Express, which operating on the same localhost as my front-facing Node/Express app. I'm trying to optimise as much as possible and I'm ...
0
votes
1answer
268 views

Optimizing mysql and apache ovh vps [duplicate]

My website is 100% mysql php so it gets slowdown and sometimes server shutdown. I'm using VPS Classic: The best cheap VPS - $2.99/month - OVH (VPS Classic 4 - 4 vCores and 8GB RAM). I want some ...
2
votes
1answer
3k views

Nginx performance when running multiple instances on the same machine

I'm trying to understand the performance impact of having multiple nginx instances (masters) running on the same machine, rather than having them all load into a single instance using different server ...
0
votes
1answer
365 views

whats the best practice to do a long query like deletion of big chunks in mysql

On production servers I need sometime to delete a few 100,000s of rows . The query is optimized but deleting at once will cause servers freeze so I do it manually in chunks deleting for example 5000 ...
3
votes
0answers
181 views

Optimal server stack for Wordpress [closed]

There are numerous tutorials/articles(some even with benchmarks) on how to create an optimized stack to run Wordpress(or any dynamic site, for that matter). The site doesn't get frequently updated(...
0
votes
1answer
3k views

NGINX and failed (12: Cannot allocate memory)

could someone be so nice and explain me how to solve this problem? in log nginx print: 2015/06/24 11:12:19 [alert] 2151#0: mmap(MAP_ANON|MAP_SHARED, 33554432) failed (12: Cannot allocate memory) ...
-2
votes
1answer
259 views

Mysql Optimization For VPS [closed]

I've a bit in a problem optimizing my VPS's (Linux / Cpanel) mysql settings. I don'n know much about Mysql and I'm using this VPS for about 50 different websites. They all had below 100 visitors daily,...
6
votes
1answer
343 views

Red Hat Linux tuning for a single application with a few TCP clients [closed]

I know Linux is built for multi-user / concurrent-process, but at the corporate level, many of them are used for single (but big) applications to support an internal service, of which serving only ...
3
votes
4answers
1k views

What is a core, and will purchasing more cores for my VPS speed up page load times?

I recently purchased a premium WordPres plugin called Hide my WP. I planned on using this plugin for my nonprofit organization's website, which is a multisite WordPress installation with an SSL. ...
4
votes
4answers
16k views

MySQL taking too much CPU

Below is my .cnf file and if I see my CPU consumption 99.99% of it my the mysqld commands. The MySQL server is connected from remote machines that update data in it frequently, but I make sure that ...
-1
votes
1answer
390 views

Tracking the slow - how to list all processes related to web-server?

I wanted to ask people in this community about administration of the Debian based web server - its a dedicated server, hosting a single website. From time to time the web site is slowing down, on ...