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

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0
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2answers
58 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 "...
11
votes
1answer
284 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 Bridge)...
1
vote
3answers
137 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
vote
0answers
118 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
vote
1answer
16 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
votes
1answer
143 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
votes
1answer
316 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 ...
0
votes
0answers
10 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
vote
1answer
104 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
votes
1answer
40 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
votes
0answers
45 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 ...
1
vote
0answers
32 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 MB/...
2
votes
0answers
98 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
votes
2answers
98 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
votes
0answers
84 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 wait,...
2
votes
0answers
62 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
40 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 (...
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 ...
0
votes
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
votes
0answers
43 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 Landing....
3
votes
1answer
41 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
vote
0answers
143 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 (rw,relatime,errors=remount-ro,...
0
votes
0answers
55 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
votes
1answer
30 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
82 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: http://52....
0
votes
1answer
106 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
69 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
votes
1answer
163 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 ...
1
vote
1answer
32 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 > /proc/sys/vm/drop_caches....
0
votes
0answers
22 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
vote
1answer
49 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
329 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
142 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
576 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
86 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
vote
0answers
18 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
248 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
38 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
85 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
vote
1answer
354 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 ...
1
vote
0answers
27 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
124 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% ...
-4
votes
2answers
66 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 ...
2
votes
0answers
255 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
239 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 ...
1
vote
0answers
18 views

Trend Smart Scan server updates thrash the disk

Every 2 hours, Trend Worry Free business updates Smart Scan. This process requires Trend to thrash through 6 gigabytes of data - this causes two issues The file cache, full of LOB data, is lost and ...
1
vote
0answers
132 views

MySQL overloading CPU at 100%+

My site appears to be getting over 1 million visits today, usually about 20,000 and for me it seems to be near-unresponsive. I've done some sleuthing and optimised Apache, fixed a bug with PHP ...
1
vote
1answer
43 views

HDD seq. read performance

I read the specs for one of the latest Hitachi HDD, https://www.hgst.com/sites/default/files/resources/USC10K1800_ds.pdf . It indicates a speed of SAS 12 Gb/s which is 1.5 GB/s. Is it the sequential ...
1
vote
2answers
33 views

Will a large number of used inodes cause a server to run slowly

I have a server that runs a Magento site. After being alerted that the available inodes were almost completely used up I found that the site had been storing session files and was not removing them. ...