48
votes
Accepted
How To Tune Apache on Ubuntu 14.04 Server
Recognize that Ubuntu 14.04 uses Apache 2 with PHP running through an mpm_prefork module, of which an editable file is in /etc/apache2/mods-enabled/mpm_prefork.conf. Also, recognize that starting in ...
- 1,508
44
votes
Accepted
Why is my bare-metal 16x 2.93GHz cores computer performing poorer than a VPS with 4x 2.5GHz cores?
Processor advancements, clock speed and IPC calculations can make it almost impossible to try to reasonably compare decade old CPUs to modern ones. Not only are the instructions per cycle going to ...
- 24.1k
32
votes
Why is my bare-metal 16x 2.93GHz cores computer performing poorer than a VPS with 4x 2.5GHz cores?
I don't want to sound terrible by emphasizing something that should be obvious here, but you're comparing a high-end server processor from 2014 to a high-end server processor from 2007.
I don't think ...
- 196k
26
votes
Accepted
How do I tell how close I'm getting to somaxconn?
somaxconn determines the maximum number of backlogged connections allowed for each TCP port on the system. Increasing it (recommended for servers) can prevent "connection refused" messages, ...
- 916
25
votes
How to measure req/sec by analyzing apache logs
This great article helped me a lot...
http://www.inmotionhosting.com/support/website/server-usage/view-level-of-traffic-with-apache-access-log
I had created a set of prepered commands that I am ...
- 431
23
votes
Accepted
Virtualization - Ten 1Gbps links or one 10Gbps link? (Performance)
1 x 10Gb link for performance.
Otherwise if a single server needs to use 1.1Gbs to another server it can't because most load balancing systems use destination MAC or IP (Which would be the same).
...
- 678
19
votes
Virtual machines and I/O heavy workload, is it ever sane?
Is it ever sane to use a Virtualized solution when performing I/O
heavy workloads?
Yep, very sane indeed, in fact for most organisations now virtual is the default and doing things on physical ...
- 101k
15
votes
Improving OpenVPN Performance
Short answer: disable comp-lzo.
I realize this is an old post, but I was also suffering from poor OpenVPN performance. I had tried everything, adjusting the MTU, changing the snd and rcv buffers, mss ...
- 151
13
votes
Accepted
What do users see when Apache reaches MaxClients?
At first, the client requests will get queued, until there is a process/thread that gets free on the apache server. So, the clients will see a delay in loading the page. See the MaxClients parameter ...
- 2,075
13
votes
How dangerous might it be - and what performance gains may be had - by turning vulnerability mitigations off on non-Internet facing servers?
The Linux kernel flag mitigations=[on|off] is a single toggle to easily enable/disable all available kernel mitigations for hardware vulnerabilities as listed here https://docs.kernel.org/admin-guide/...
- 1,713
11
votes
Options for performance improvements on very big Filesystems and high IOWAIT
I have a similar (albeit smaller) setup, with 12x 2TB disks in a RAID6 array, used for the very same purpose (rsnapshot backup server).
First, it is perfectly normal for du -hs to take so much time ...
- 45.5k
10
votes
Virtual machines and I/O heavy workload, is it ever sane?
Is it ever sane to use a Virtualized solution when performing I/O heavy
workloads?
Does a database server regularly pulling 1gb/second random IO count? Have one here.
Or a virtual file server ...
- 51.4k
8
votes
How to raise max no of file descriptors for daemons running on Debian Jessie?
You can use "ulimit" in the "start" section of the pgbouncer init script:
/etc/init.d/pgbouncer:
[... snip ...]
case "$1" in
start)
# Check if we are still disabled in /etc/...
- 371
6
votes
Options for performance improvements on very big Filesystems and high IOWAIT
This Filesystem stores a huge amount of small files with very many SEEK operations but low IO throughput.
🎉
This is thing that catches lots of people nowadays. Alas, conventional FSes do not scale ...
- 9,353
6
votes
Packet drop on HP ProLiant DL360 G9 running RHEL 6.10
Check the driver version. There was the bug with correct accounting of the rx_no_dma_resources, when the rx buffer is full. So check the length of the ring buffers (ethtool -g <iface>) and ...
- 4,982
5
votes
Accepted
ESXi very slow with WD reds
What's the question here?
You don't seem to be comparing apples-to-apples. So I'm not sure if you just want this system to run like your other systems, or if you really care about the cause of the ...
- 196k
5
votes
Accepted
measuring network throughput with netperf
That image says that the maximum UDP transfer rate over 1gbps ethernet is 119635891 Bytes per second.
Multiple 119635891 with 8 (one byte is 8 bits) and you get 957087128 == 957,08mbps
- 19.6k
5
votes
Stand alone single thread optimized server vs vm running on VMWare
You are correct in your assumptions. For your particular case stacking Mhz's instead of vCores is a right way to go. Take a look at this processor: (features 4x 3,5-3,7 Ghz physical cores + HT).
...
- 4,897
5
votes
nfs server getting many rpc-srv/tcp: nfsd: sent only 700260 when sending 1048708 bytes - shutting down socket
This site reports some more suggestions, including increasing the NIC txqueuelen. These suggestions are mainly aimed at high latency networks, however I noticed that under Fedora24 Infiniband ...
- 51
5
votes
Serving a static website with nginx. Response time over 600 milliseconds. What’s wrong?
I re-ran the test from Mumbai with no bandwidth restriction and got a TTFB of 237ms for the page and 7ms for a static resource.
You restricted the test to 2G, which is very low bandwidth.
So the ...
- 31.2k
4
votes
Find out which task is generating a lot of context switches on linux
In newer kernel version
sudo perf record -e context-switches -a # record the events
# then ctrl+c
sudo perf report # inspect the result
This will give you the exactly result about context-...
- 141
4
votes
NFS Over OpenVPN: Top Performance Boosters
I have played with NFS configuration with openvpn on ADSL connection, I have tried different NFS mount options, here you can find the complete post:
NFS over OpenVPN over ADSL(or slow connection)
I ...
- 171
4
votes
Mysql innodb_buffer_pool_size in relation to innodb_buffer_pool_instances
innodb_buffer_pool_instances:
You cannot see its effect unless innodb_buffer_pool_size is few gigs, dividing the buffer pool into separate instances can improve efficiency. This is also a tuning ...
- 656
4
votes
Accepted
Dual-port RDMA Throughput Issue
I think the bottleneck here is the PCIe link between the ConnectX and the host. The ConnectX-3 has a Gen. 3 x8 PCIe connection, which is bound to a theoretical maximum of 63.04 Gbps (according to this ...
- 272
4
votes
Accepted
How do I tune a single-threaded server to be amazingly fast?
Providung a laundry list of tunable parameters here will do little to put your server into a better state. Performance tuning is a process, not a task. Measure, tweak, and measure again. Restrict ...
- 306
4
votes
php memory_limit vs kubernetes resource memory limit
Setting up container resource requests and limits is the first step towards using resources effectively in your Kubernetes cluster. After you set them, make sure you have monitoring and alerting in ...
- 455
4
votes
Accepted
Is it possible for Windows clients to carry out external queries through an alternative DNS server directly?
No, the conditional forwarder are configured on the DNS server side, not on the client side sadly
I would deleguate a local server with a DNS role that could redirect to the remote DC all your domain ...
- 16.6k
4
votes
Accepted
MySQL LOAD DATA INFILE: Better Server, Worse Performance
Here's what seems to have been causing this behavior:
Per the Azure documentation, the Basic tier server on Azure comes with "variable" IOPS whereas the Memory Optimized server comes with a fixed ...
- 71
3
votes
How To Tune Apache on Ubuntu 14.04 Server
What you can raise MaxRequestWorkers to depends on how much RAM each of your httpd / apache processes takes up. If each one takes up 50MB (just picking a random number), then every 20 request workers ...
- 973
3
votes
Will noatime on a tmpfs volume improve performance?
In theory I agree with what @kasperd said. However, I decided to try the change on my very busy tmpfs backing munin data, and it immediately provided an 8% decrease in total munin processing time.
...
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Only top scored, non community-wiki answers of a minimum length are eligible