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

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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 ...
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1answer
39 views

How to reduce “Connecting” time incurred for a request

I am trying to optimize speed of website and during this process I have found that. A connecting time of around 620ms is incurred everytime I request a page. Please see screenshot below for detailed ...
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0answers
10 views

Limiting Oracle instances resources with Cgroups?

Is it possible to limit the amount of resources (I/O, CPU and Memory) a Oracle instance can consume using only cgroups? (no containers or virtualization) The reason I wanna do that is because I want ...
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0answers
19 views

Performance concern with hosting large clustered DBs on VPS cloud servers

I wonder if anybody else bumped into this issue? You get a couple of beefy 12-core VPS instances in some cloud like DigitalOcean and set up a database on them in "active-passive" cluster ...
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15 views

Are changes since snapshots still stored as changelogs?

It's been four years. Is the accepted answer of this question about VMWare still accurate? In other words (in case for some reason that link ever breaks), is this still true? When you create a ...
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47 views

ncftp vs common ftp speed

I have very different download speeds with this two ftp clients. Ncftp with standard configuration downlaods at 7MB, while ftp does it at 80MB (connection between dedicated server and FTP Backup ...
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0answers
35 views

httpd processes cpu spike to 100%+ every xx seconds

My first post, unfortunately due to an issue on my dedicated (Linux Centos 6) server running some personal and one commercial website. Server version: Apache/2.4.18 (Unix) Server built: Mar 7 2016 ...
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1answer
28 views

Getting file size before download on a proxy server [closed]

We're working on building a multithreaded proxy file server in C, where we receive a request and retrieve it from another location using the libcurl library. The library gives you the option of ...
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2answers
49 views

Disk IO Rate: What causes it and what does it mean to me?

I just got a mail from Linode saying that my account "has exceeded the notification threshold (1000) for disk io rate by averaging 1017.36 for the last 2 hours. " My question is just out of curious: ...
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1answer
89 views

FTP transfers slow on a long fat pipe

We've recently gotten new internet - 100Mb/s fibre - and have been complaining bitterly to our new ISP about transfer speeds to some FTP servers in the USA (300ms away). To one server in particular, ...
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11 views

How can I get a nginx & php server to use much more system resources?

I'm running a local setup. Crunching some largish 100mb json files via php running on nginx. I'm also doing some mysql stuff, checking through tables with about 90k rows, matching data from the json ...
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89 views

MongoDB high page faults every 15 minutes, delayed readers

We have a relatively small MongoDB production replicaset. We do about 100 operations per second -- balanced reads and writes. Every 15 minutes or so we see a spike in response time on reads, and in ...
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57 views

Mongodb, we can't go over 100 insert/sec on 200iops HDD

Thanks in advance for your help, we get a strange behaviour in mongodb. So we have a cluster of 20 shards, each composed of 1 master and 2 slaves. This database has a heavy load of write only. However ...
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1answer
26 views

how to identify and report bad RDS hardware

Recently we [finally] migrated all of our production hardware from the deprecated default networking into VPCs including EC2 and RDS nodes. Everything went pretty well except when we started to run ...
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1answer
239 views

Why is zfs/btrfs recommended for an lxd host?

Note that for maximum performance, it's recommended to have /var/lib/lxd on a btrfs filesystem or setup ZFS or LVM and configure LXD to use a ZFS pool or LVM VG. Source Why is that? I.e. ...
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1answer
28 views

Managing sudden peak in traffic for event ticketing system

I am going to be managing an event ticketing system for a specific event. I think we will probably be expecting generally low traffic, although there's likely to be a few sudden peaks of traffic (to ...
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1answer
28 views

Which bandwith can i expect, when i´m running a SATA SSD on a SAS interface?

So, i know this question had been asked before. I consider to buy a SSD for my Server, because i kinda hate the SAS HDDs in there. I thought: If i connect a SSD, which, in fact, handles way more ...
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1answer
73 views

Fastest triggering of realtime anti virus scan

I have the problem, that in each backup of my mail system (File based archive on Windows Server 2012 R2), errors occur while backing up virus-infected e-mail attachment files. This is caused by the ...
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0answers
28 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 ...
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19 views

Oprofile events are not available

I run an Intel(R) Xeon(R) CPU E5520 @ 2.27GHz and I've just started to use Oprofile. I want to measure some events like the BUS_REQ_OUTSTANDING and BUS_TRAN_BRD but are not available. Is ...
2
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1answer
53 views

Filesystem Performance for LUKS Encrypted Volumes?

As you can format a LUKS volume with any filesystem you want, are certain filesystems better-suited to IO performance against an encrypted filesystem? Specifically, I'm wondering about a loop device ...
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26 views

Bad performance on ocfs2 with many files

i am managing a small science server infrastructure with an ocfs2 storage. On the storage are about 9.000.000 files consuming 4,7 TB. The files itself a really small around 500KiB-1Mb. The problem is ...
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28 views

Server Specs for browser game that hugs cpu

Our team have developed a web browser game, our servers are using nginx and php-fpm to host the website. the game consist of two parts an api and the game itself. both applications reside on its own ...
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31 views

Comparing 1x Xeon multi core vs 4x UltraSparc IV

I'm in the process of reviewing specs for hardware running an Oracle server. The new hardware will be running using Xeon processor compared to the old servers (Solaris) running on UltraSparc IV. So ...
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2answers
53 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 ...
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1answer
244 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 ...
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3answers
107 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 ...
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0answers
104 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 ...
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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 ...
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1answer
100 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
234 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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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 ...
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1answer
84 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 ...
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1answer
32 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 ...
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0answers
43 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
30 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
89 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 ...
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2answers
72 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 ...
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78 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
60 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
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1answer
36 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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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 ...
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42 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 ...
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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 ...
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122 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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46 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?
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1answer
29 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 ...
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3answers
77 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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1answer
95 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 ...