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

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0
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14 views

nginx / node server TTFB very high sometimes

I currently have 2 nodes app on a nginx server behind is a mongo db and a elastic search instance. I currently face serious performance issue, this is not related to an overload of number of user, ...
2
votes
2answers
71 views

How can SSD write performance be dramatically different on two identical servers?

I am renting two identical physical servers (at Serverloft). These servers come with 2x512 GB SSD disks, and I've set them up with mdadm in a RAID1. The disks are locally installed in the server. The ...
0
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0answers
14 views

Gathering Performance Metrics (RAM, CPU, etc) AWS & Azure

We're developing a cross cloud plane performance metric harvester, to collect various performance metrics, but the top 3 being RAM usage, CPU Utilization and Disk Utilization. I know CloudWatch will ...
1
vote
2answers
34 views

How to balance elasticsearch (java) on a very powerful machine?

On a 16 core XEON class, 128GB RAM RHEL server I want to deploy elasticsearch. What is preferable performance-wise? Have a huge elasticsearch process to use all resources on the native host? Break ...
2
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0answers
8 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 ...
0
votes
1answer
31 views

How to find which db/collection/query triggers disk read?

We're running a MongoDB 3.0 server with multiple users accessing it and we're experiencing very frequent disk reads by mongod process utilizing our SSD drives to 100% During these peaks the page ...
0
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0answers
22 views

We are constantly getting CPU Spikes and site slows down [duplicate]

Our website works fine and fast, then out of nowhere cpu spikes to 100% site becomes really slow and after 10 minutes it is back to normal, this is constantly happening. How would one diagnose this? ...
1
vote
1answer
183 views

Huge performance penalty in gbit link with ip forwarding / masquerade through clear VPN tunnel

I have a problem with IP forwarding between my home computer and a remote server (from online.net). My home connection is a 1 Gbit/s FTTH and the remote server has a 2.5 Gbit/s bandwidth. The context ...
-1
votes
1answer
35 views

mpm_prefork values for 2-4 GB RAM [duplicate]

I have bought new linode (1GB). On this page :https://www.linode.com/docs/websites/lamp/install-lamp-on-ubuntu-16-04 Linode says: Below are the suggested values for a 1GB Linode: ...
4
votes
2answers
54 views

Massive performance degradation on sustained sequential write

I'm in the process of migrating data into LUKS partitions. Now that the operating system drive is running off LUKS, I tried to start migrating the data drives. Then the server stopped responding. ...
-2
votes
1answer
19 views

Calculate CPU parallel-processing performance [closed]

I have made a script in C where I do prime number calculation and can specify to perform concurrent calculations on multiple CPUs. Based on the results I have gathered real and user time with 1, 2 and ...
0
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0answers
20 views

RAID 1 disk sequential read/write speed inconsistent

I have an issue with 2 of my servers, and I'm not sure what's going on. The setup is the same for all my servers: C: 2 SSD 512GB in RAID-1 D: 2 SSD 512GB in RAID-1 The servers are DELL's, the ...
1
vote
0answers
9 views

Windows Server Backup Snap-In Initializes/Moves Extremely Slowly

I have an SBS-2011 box. The WSB snap-in consistently takes 10+ minutes to move beyond 'Reading Data'. After the snap-in finally initializes I experience the same behavior when performing a recovery. ...
1
vote
1answer
77 views

How to identify the cause of 100% CPU usage in Azure App Service?

I have five apps in an Azure App Service Plan, all different copies of the same app for different clients. It's an ASP.NET MVC app with an SQL database. This morning I woke up to slow and ...
-2
votes
1answer
41 views

Analyzing server performance [duplicate]

Analyzing server performance Hi we have recently finished work on one ecommerce site which is built on opencart 2.x and site has around 1k products. The site is currently running on VPS server. from ...
0
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0answers
14 views

Servers experience intermittent CPU “sensitivity”

We have a strange intermittent issue with a few servers where their CPU's become more "sensitive" to load. By this I mean that processes that generally run without issue, suddenly take up ...
0
votes
1answer
18 views

Best performance- and backup-strategy with running multiple Webapps and databases on dedicated servers

my company is soon going to move our webservice-hosting to a new hoster and therefore i'm currently planing how everything will run in the future. I have to deploy at least: MsSQL-Database Server ...
1
vote
0answers
21 views

HTTP/2 and SPDY running together in Apache

I have the latest Apache installed and currently support HTTP/2. Can I setup SPDY and run it together with HTTP/2? The goal is to also take advantage of the SPDY for browsers that do not support ...
3
votes
2answers
73 views

Measuring 40Gbe performance

I've connected two hosts via a 40Gbe fibre link and would like to determine a baseline for data transfer between them. I'm seeing relatively low speeds (~620MB/s). It seems that the signalling rate is ...
2
votes
3answers
103 views

SAS / SATA max number of connected disks vs performance

I would like to understand following things: When I have a motherboard with SATA 6gb/s and 8 ports, does it mean that every single port is able to provide 6bg/s speed to disk that is connected over ...
2
votes
0answers
15 views

Forking loads disk

I have a prefork/fork daemon. By atop I see, that master-process often consumes disk: PID TID RDDSK WRDSK WCANCL DSK CMD 16830 - 7264K 48696K 18624K 10% our daemon From strace I see, that it ...
3
votes
3answers
352 views

How to load balance with respect to memory, disk usage, and other attributes

I've found load balancers such as NGINX but those seem to work only by keeping in mind CPU usage and network traffic. How would I load balance with respect to other variables such as the amount of ...
-2
votes
1answer
112 views

top: sy higher than 70: What is going on here?

From the man page of top: sy: time running kernel processes The sy-value has peaks with values above 50, and then goes down to about 5 again. What could be the root of it? Here are two ...
1
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0answers
17 views

rsync: Maximum nice to keep system responsive

Unfortunately a background rsync reduces the responsiveness of a server. I search a way to have maximum niceness for this background task, to keep the server respond fast. My current wrapper ...
1
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0answers
30 views

IIS Performance Issues with Flat Files (html, css, js)

We're running an Windows 2012R2 VM with IIS 8.5 with the purpose of serving out flat files, no ASP.NET or other dynamic content is in use. The server is configured to map 5 sites to the same IP & ...
5
votes
2answers
488 views

How can I chose a max load threshold depending on the number of available cores?

I have a pipeline that runs some computationally intensive tasks on a Linux machine. The script that launches these checks the current load average and—if it is above a certain threshold— waits until ...
1
vote
3answers
59 views

How to improve AWS RDS Performance - Heavy read write updates

After searching and reading as many posts, comments and discussions I could find I did not find one specific to my issue. I have multiple AWS EC2 deployments with a single RDS all in the same ...
3
votes
0answers
52 views

Improve SSL Performance with Nginx

We have Nginx in the front of our system and we Proxy to Apache at the back. We use SSL/TLS for our connection. Question: Is Nginx the best option to terminate SSL/TLS connections in terms of ...
1
vote
1answer
38 views

TcpTimedWaitDelay is missing in Windows Server 2012

Suddenly my server log shows: An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full And I googled and found these links as ...
1
vote
1answer
35 views

Performance impact enabling intel vt-x

I have a rather unusual question: What is the performance impact when you enable vt-x and you don't need it? I ask this because all of the new servers I receive have this enabled by default in the ...
0
votes
1answer
27 views

What is the best way to analyze data captured from sar?

I've got some sysstat data that has been captured from servers with SAR, and I'm unsure what is the best way to analyze that data. I've found ksar, but it seems to be quite old and out of date. I'd ...
0
votes
1answer
20 views

Improving I/O rates for EBS snapshot backed volumes

I'm working with a system that takes a set of 42 rotating daily EBS snapshots of each of its numerous (40) volumes for disaster recovery purposes. EBS volumes are aggregated into a RAID volume. A set ...
7
votes
1answer
112 views

Sluggish performance on NTFS drive with large number of files

I am looking at this setup: Windows Server 2012 1 TB NTFS drive, 4 KB clusters, ~90% full ~10M files stored in 10,000 folders = ~1,000 files/folder Files mostly quite small < 50 KB Virtual drive ...
-1
votes
1answer
38 views

Which raid array will be best practices with seven 1.2 tb hdd system

I have a server which have seven 1.2 tb hard disks. I have to create raid array but i don't decide which raid i use? First of all, first and most important matter is security. At any cost i must not ...
0
votes
1answer
15 views

Increase openfire memory to larger values

We use OpenFire for XMPP messages. We have some memory issues(OutOfMemoryError), and therefor we would like to increase memory. I know how to increase memory using VM options and we were able to ...
0
votes
0answers
25 views

lower tcp throughput than expected

I've conducted some tests which measured tcp throughput via wireless and wired connection. (a) was wired link between my desktop and my home router. (b) was wireless link between my desktop and my ...
2
votes
1answer
58 views

Why might 'mpstat' and 'pidstat' disagree about CPU load levels?

I'm monitoring a mysql process in ubuntu 12.04 using mpstat and pidstat, simultaneously. While debugging its CPU usage, I noticed something unusual. While both tools agree that CPU load is occurring, ...
0
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0answers
32 views

Reduce Connecting time to server for inital request

I am struggling with decreasing load time of inital html page request. It is consistently above 800 ms however other websites they load in less than 300 ms. In this load time GTMetrix shows more than ...
0
votes
0answers
19 views

Does decommissioning nodes on hadoop cluster hamper performance?

I have 120 node Hadoop cluster, I have removed around 14 nodes in 7 days (each day - 2 nodes were decommissioned) Now users are facing some performance issues, does this decommission really matters. ...
4
votes
4answers
1k views

RAID 10 - many slow disks vs fewer fast disks

I am looking to buy HDDs for a single server which will be used as development server. The server will use ESXi as hypervisor and will have some but not too many virtual machines (web server, database ...
0
votes
1answer
25 views

Speed: nginx serving static content even faster: fixed folder ; how can I

we run centos and nginx one of latest versions in 2016. We use 1 media directory with some underlying subdirectories. FTTB for php is 200ms which is very fast - but now I discovered that the JS CSS ...
1
vote
0answers
50 views

Slow gigabit speeds with Ookla speedtest software

We have 2 speedtest servers (RHEL 6.7) sitting on 10GB links with a 10GB pipe between the two. The servers are separated geographically by about 256 miles but traceroutes look very good, with 4 hops ...
1
vote
1answer
33 views

How can I determine which files have high I/O in Windows?

In trying to reduce the storage bottleneck on a Windows server (2008 R2) I need to find the files that have the highest I/O over a long period of time (aka 'hot' files) so I can move those to SSD ...
0
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0answers
23 views

Real memory usage on Linux and Private_Dirty

On Linux, is using Private_Dirty value from smaps a good way to measure real process memory usage? Thanks
1
vote
1answer
64 views

Hardware performance penalty for Hyper-V Generation 2 VMs

I have the following configuration: Windows Server 2012 R2 OS installed on baremetal with Hyper-V. OS is installed on RAID1 850 PRO drives. Windows Server 2012 R2 Guest OS Generation 2 VM is located ...
0
votes
0answers
21 views

Why in my index in a cold situation that slow?

We have a table CREATE TABLE mytable ( ... myfield bigint, ... ) and an index CREATE INDEX fk_fk18edb1cf49a32f88_idx ON mytable USING btree (myfield); and a simple query SELECT count(*) ...
0
votes
0answers
47 views

Disk performance drops in VMWare ESXi 4.1 / 5 Linux Guest

I'm benchmarking disk write performance using this command: dd if=/dev/zero of=/mnt/test.dmp bs=1M count=256 conv=fdatasync After a random time and random number of attempts, the file system ...
1
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0answers
24 views

iperf actual send rate always lower than the expected target bandwidth until some equilibrium reached. Why?

I did an UDP iperf 2.0.5-Ubuntu test between two VMs on the same hypervisor. As can be seen in the iperf output below I started my first test with "-b 686M" flag. However, iperf reported that it was ...
2
votes
1answer
68 views

Is this btrfs snapshot removal performance normal?

I have several boxes running Debian 8, dovecot and btrfs. I'm using btrfs snapshots for short term backup. For this purpose I keep 14 snapshots of the mail subvolume. Performance is OK until it comes ...
1
vote
1answer
36 views

Intermittent Server Performance Degradation Troubleshooting

I have been troubleshooting an intermittent server performance issue for too long and I am running out of ideas. I am looking for any suggestions as to how I might be able to identify the cause of ...