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

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1answer
16 views

Guest OS 100% utilization, 'Total Run Time' is about 60%

I have ran CPU stress test on linux HyperV VM. Linux reports 100% CPU utilization, but "Hyper-V Hypervisor Virtual Processor(*)\%Total Run Time" metric shows about 60-70%. Is it possible to obtain ...
4
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0answers
25 views

OpenVPN low performance. Do I have MTU problems? Dumps inside

I have problems with an OpenVPN tunnel which does not reach line speed. The gateway is a Debian Jessy virtual server hosted at OVH. The client is either my freebsd 10.2 homeserver (Intel I3 Ivy ...
1
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2answers
41 views

How can I determine the performance penalty of VT-d vs. baremetal?

I am looking to configure my server in a slight odd way to create a private cloud setup. I have to take the HBA that my storage disks are tied to and pass it into a VM (probably xen) to allow the ...
1
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0answers
33 views

What's your experience with the AWS NAT Gateway performance?

In December/2015 Amazon launched their VPC NAT Gateway service which is basically a managed alternative to creating your own (and it looks very good in comparison to NAT instances). I was just about ...
1
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1answer
13 views

Linux top in RES what does the 't' suffix stand for

When monitoring my system with top, I noticed that under RES some values have a 't' suffix, but I can't see any indication of what this means. PID USER PR NI VIRT RES SHR S %CPU ...
4
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1answer
47 views

SQL Azure insert query ten times slower on V12 than V11?

I noticed performance degradation about two weeks ago impacting one of our applications with an SQL Azure backend. It's running on V12 on tier S1 90% of the time, sometimes scaling to S2, S3 or P1. ...
3
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1answer
37 views

php-fpm and nginx @ high CPU usage?

My server is with DigitalOcean with the following plan: 2 Core Processor 2 GB Memory My website is receiving thousands of visitors, however, both CPU cores are @ 100%: The issue seems to be with ...
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0answers
6 views

Performance Impact of a SSD on Jetty

I was wondering if anyone has experience or data if the overall performance of a request is impacted by a SSD when using e. G. Jetty with all necessary data loaded to the RAM. I would expect no ...
1
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1answer
22 views

Nginx Stress Test with httperf - Large Data Transfer Differences from Apache Server

I'm running a simple httperf stress test on a quad-core Nginx server, pointed at an HTML/PHP document. Large connection rates quickly begin experiencing high connection and response times (see the ...
0
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1answer
17 views

Why my disk elevator is set to “deadline”

I have CentOS 6.x Linux server with kernel 2.6.32-573.8.1.el6.x86_64. I did some checks today and I found that disk elevator is "deadline". [root@srv ~]# cat /sys/block/sda/queue/scheduler noop ...
2
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0answers
29 views

What are the various factors that limits disk read and write speeds and on a network? [closed]

How to choose a server which: has high I/O performance of storage is highly flexible in terms of adding more storage So, basically these servers should act as storage servers for OST in lustre ...
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0answers
18 views

Persist statistics data from Postgres' stats_temp_directory on demand

We are investigating I/O load in one of our VMs and possibilities to optimize it and it showed that most of the load is generated by the stats collector of PostgreSQL. It jumps between 3,5 and 6,5 ...
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0answers
16 views

Debug slow lan (ssh, nfs) file transfer

I've got two linux boxes attached to a gigabit switch. They both have gigabit NICs, cables are cat7. Testing the network with iperf shows a fast connection but transferring files with rsync, scp, or ...
0
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2answers
32 views

Apache TLS (SSL) Performance

We are running a fairly powerful dedicated server with a Xeon CPU, 32GB RAM, and RAID SSDs running Centos 6. Yet, we are still seeing HTTPS add over 100ms to our page download time. Is there anything ...
0
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0answers
26 views

Synology DS1813+ RAID 5 with iSCSI IO wait perfomance issue

I'm have RAID 5 on Synology DS1813+ (DSM Version: DSM 5.0-4493 Update 4) with 8 ST4000DM000-1F2168 disk, usind as NAS and iSCSI/NFS targer for ESXi. In low read/write rate from disk have more io ...
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0answers
16 views

Upload speed for 100 visitors per day [duplicate]

I'm trying to setup a small business with my Asp.net web application. My initial target is, max 100 visitors per day and I can manage a 2.5 mbps internet speed which has 2.5 mbps upload speed with ...
-2
votes
1answer
29 views

How is download speed calculated [closed]

if I am having a 5ms ping to a server and download speed of 1 megabyte per second, how do I know exactly how this 1 megabyte per second is calculated/limited in terms of internet/network ...
2
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0answers
45 views

Unexpected discrepancy between write and read performance using cryptsetup 1.4.3 and 1.6.6 on Debian Wheezy (7.9) and Debian Jessie (8.2)

I have been setting up a raid1 array and have set up an encrypted medium using cryptsetup with default options. The raid arrays are supposed to use 2 drives, but for the moment, I only have 1 drive in ...
0
votes
1answer
23 views

MySql ignores memory settings

I'm using MySql community server 5.6 on Ubuntu 15.04, I have /etc/mysql/my.cnf (no other config files). I've made changes to it and restarted MySql. When I use such query SELECT @@key_buffer_size ...
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votes
1answer
12 views

SQL Server DB and Instance performance [closed]

I have some interesting situations. I have two different application DB's(MS SQL Server DB's) on two different server. One DB is already on VM server and working fine. Now I have to migrate the ...
14
votes
2answers
1k views

Virtualization - Ten 1Gbps links or one 10Gbps link? (Performance)

I have a machine that has several VM's (5) and 3 physical networking cards (with each 2 ports), with a total of six 1Gbps ethernet ports. I have a SPF-capable switch, having a total of 48Gbps ...
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0answers
7 views

How to calculate Hardware requirements to send push notifications to GCM [duplicate]

I am gathering hardware requirements for system (up to 100M users) that would be firing Push notifications and nothing more. It would receive a signal to send message and then would select all users ...
0
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0answers
20 views

asp.net website intermittent slowness

I have published a asp.net web application in azure which has the configuration of D-13. The domain has been registered with GoDaddy. These are the list of webpages I am using Login.aspx ...
3
votes
1answer
30 views

Finding SQL Server Bottleneck - not CPU, IO, available memory

I'm trying to identify the bottleneck on a new SQL Server implementation (2012 Enterprise). I've been running some meaty queries/ETL jobs which are taking a considerable time - but I'm having ...
1
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0answers
49 views

KVM bad IO sync performance in Linux guest

I'm setting up virtualized Ubuntu 15.10 guest inside Ubuntu 15.04 server using libvirt and KVM. Storage in host system: # mount | grep ext4 /dev/sda1 on / type ext4 ...
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0answers
23 views

How to find the bottleneck for slow rsync

I want to find the bottleneck for a slow rsync. I see these parts (on byte flow order): IO on source CPU on source Network CPU on destination IO on destination How can I debug this?
0
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1answer
21 views

Low iops,read and write performances

We are currently testing our using ZFS on Linux as a storage platform for our VPS nodes but we don't seem to be getting the performance figures we expected. Can you please provide some suggestions as ...
2
votes
3answers
64 views

Check the cause of slow loading time among different server

A e-shop has developed using perstashop and put to the three server: the first 2 are amazon EC2, should be same setting Server 1: http://be-pure.com/en/women/3-slim-y-tank.html Server 2: ...
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votes
1answer
43 views

Will adding CPU cores or RAM to my cloud server improve speed in my situation? [duplicate]

I have a Siteground cloud server, and I know nothing about servers. It hosts 8 websites, although 3 of them have their own dedicated IP addresses and cPanels. It's on a Linux server, but there's ...
3
votes
1answer
51 views

Decreased performance of Mysql after superior hardware upgrade

I am quite new to Percona/database servers and i dont know how to approach the following issue. Couple of days ago i upgraded the hardware of a percona cluster (3 nodes) servers with a much more ...
0
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1answer
49 views

MongoDB 80,000+ insertions per second

To test my MongoDB 3.2 / WiredTiger on CentOS6, I use the script from http://vladmihalcea.com/2013/12/01/mongodb-facts-80000-insertssecond-on-commodity-hardware/. Here I list the script (a little ...
0
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0answers
8 views

Is it possbile to cache pdf documents on the netscaler?

I have a file server which gets pretty overloaded quickly because it is serving huge pdf documents. I have a netscaler in my enviroment as well, and I was thinking of caching them in some way on the ...
1
vote
1answer
29 views

What is the “right way” to combine sync and drop_caches?

When I need to do echo 3 > /proc/sys/vm/drop_caches with a sync beforehand, is it better to use sync && echo 3 > /proc/sys/vm/drop_caches or sync ; echo 3 > ...
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0answers
15 views

How do I diagnose an intermittent ADSL issue

A few weeks ago, we started seeing brief intermittent outages of our connection to the internet. Our connection to the internet looks like this: Internet <---> DSL Provider <---> ADSL ...
1
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1answer
31 views

Apache - delay over HTTPS but not HTTP

I have a problem with an Apache 2.4.7 on Ubuntu 14.04 (almost default settings), virtual cloud server. On a medium server load (about 2/3.0 cpu usage and tons of free memory) the time for ...
4
votes
3answers
254 views

Generating a lot of dirty pages is blocking synchronous writes

We have processes doing background writes of big files. We would like those to have minimal impact on other processes. Here is a test realised on SLES11 SP4. The server has massive memory, which ...
0
votes
1answer
44 views

Router - huge difference in Tx vs. Rx

I have two computers: (B) Banana Pi - 1 Gigabit Ethernet, Wi-Fi (supports 802.11n) (D) Desktop PC - 1 Gigabit Ethernet, Wi-Fi (2x2 MIMO, supports 802.11n) And (R) Mikrotik RouterBOARD RB951G-2HnD ...
2
votes
2answers
85 views

DRBD terrible sync performance on 10GigE

I've set up a pair of identical servers with RAID arrays (8 cores, 16GB RAM, 12x2 TB RAID6), 3 10GigE interfaces, to host some highly available services. The systems are currently running Debian 7.9 ...
32
votes
2answers
4k views

Why is my bare-metal 16x 2.93GHz cores computer performing poorer than a VPS with 4x 2.5GHz cores?

I have a written a piece of multi-threaded software that does a bunch of simulations a day. This is a very CPU-intensive task, and I have been running this program on cloud services, usually on ...
2
votes
1answer
64 views

Side-effects of having different Memory (RAM) in a server? Example 1600 Mhz and 2100 Mhz [closed]

I know that you should always have the same memory clock speed and in best case even the same manufacturer meaning the same RAM Module. But what happens if you use for example the following setup: ...
1
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0answers
13 views

Long Response Times for Reads via FCoE

We're getting some intriguing performance with our new FCoE environment, and I was hoping that people could let me know if what we're seeing is expected behaviour. Our switching environment consists ...
4
votes
4answers
232 views

Which VM needs more resources?

I have a physical server which runs 8 virtual machines with virt-manager and kvm. Since one VM is not needed any more, I want to give the remaining virtual machines more resources. I'm looking for ...
0
votes
1answer
37 views

Which memory settings to use for this MySQL server? [duplicate]

I've been looking in a lot of places so far but I couldn't find any articles about how much memory to allocate to MySQL based on server size. I am about to deploy a website on a relatively small ...
3
votes
2answers
79 views

Uneven disc throughput in RAID1 configuration

I am having performance issue caused by slow IO in server which has two identical SSDs in RAID1 configuration. By using "atop" noticed that discs usage is no even: DD | md2 | busy 0% ...
1
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1answer
180 views

Possible DNS Server memory leak

I have a Windows Server 2012 R2 physical server running AD DS, DNS roles. Very frequently DNS Server process starts consuming a lot of memory. In Task Manager > Details > Analyze wait chain - I ...
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0answers
11 views

Varnish ESI Streaming Response - Is it possible NOT to stream the response

We use Varnish (4) in front of an application which contains a few ESI blocks. What we are seeing (as expected) is that varnish streams the response from the server as soon as our backend responds to ...
0
votes
2answers
104 views

Reduced performance in mysql after upgrade to 5.6.27

Our application was using MySql version 4.0.24 for a long time. We are trying to migrate it to version 5.6.27. But, on testing the performance on 5.6.27, even the simple selects and updates are 30-40% ...
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votes
2answers
56 views

For php webserver, what is faster, 1x 24-core server or 3x 8-core servers? [closed]

Pricing at Dell, it seems I can either get a single R430 or 3x R220's. The R220's would have 4C/8T processors, giving 24 threads. The R430 would have 2x 6C/12T processors giving again 24 threads. For ...
1
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0answers
143 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 ...
5
votes
2answers
157 views

Page load long stall times. What is this? [closed]

I have been studying the performance of a website I am building, and notice a curious thing that I can't find the answer to: two requests (always the same two) mysteriously have prolonged stalled ...