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

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1
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0answers
42 views

Nginx: Optimal map_hash_max_size and map_hash_bucket_size for 1M map?

I have 1M static rewrite rules and using this map configuration. How to determine the optimal values for map_hash_max_size and map_hash_bucket_size? I want to optimize for memory consumption. The ...
1
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1answer
42 views

nginx no speed limitation for a connection

I have a server with nginx installed on it to serve some files for downloading. I also didn't change default configuration of nginx. Problem is that when I try to download from this server it seems ...
0
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0answers
70 views

Slow FTP download speeds on Synology DiskStation

We just got a Synology DS2415+ NAS which is connected to internet via a FIOS 300/300mbps connection. I am testing download speeds from a remote location with a 200mbps download connection. When ...
1
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0answers
44 views

IIS hanging when running Active Reports, possibly splwow64.exe

We have a Windows 2008 R2 web server running our web app on IIS and when running a particular page which generates a PDF (using Active Reports https://activereports.grapecity.com/) it takes between 1 ...
3
votes
1answer
87 views

NFSv3 client differences in read/write performance

I'm taking care of a few servers that make relatively heavy use of a NFS filer. At crunch time a single server sends about 2k reads + 2k writes per sec to the filer. According to nfsiostat at these ...
2
votes
1answer
88 views

Unexpected File Download Slowness After Enabled SPDY on Nginx

A simple WordPress static site run entirely on https. Nginx conf here: http://pastebin.com/BrP0LThT Only difference before / after is: listen 443 ssl; listen 443 ssl spdy; Nginx ...
1
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0answers
14 views

What is involved in adding ZFS cache stats to orca?

I am interested in looking to add ZFS cache stats into existing orca performance monitoring that we have. Particularly, I am interested in the output of echo ::memstat | mdb -k Am still in the early ...
1
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2answers
201 views

Optimize Linux file system for reading ~500M small files

We're seeing performance problems on a file system that contains ~500 M files that are relatively small (typically tens of kb) and ~150 K directories. Files access is predominantly reads and writes ...
0
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0answers
9 views

Does Intel's FlowDirector work for multicast traffic?

FlowDirector works by sampling outgoing packets, and establishing a core<->flow association so that when packets come in, it can lookup which core to send it by way of the usual RSS 3 or 5-tuple. ...
0
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1answer
56 views

Delaying packets with libnetfilter_queue

From my Raspberry Pi configured as an access point, I set the following rules: sudo iptables -I FORWARD -p tcp --sport 25 -j NFQUEUE --queue-num 0 sudo iptables -I FORWARD -p tcp --sport 80 -j ...
7
votes
1answer
291 views

Why is FileZilla so much faster than PSFTP?

I'm using FileZilla 3.10.3 and PSFTP 0.63 (PuTTY). Can anyone help me figure out why the throughput I get is so drastically different between the two clients? It can't just be a shortcoming of the ...
0
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0answers
71 views

Why a VPN slows down LAN access?

We have an access server providing VPN to some of our clients and the workforce with laptops. They usually connect from outside of the office, and everything works fine. However, for simplicity and ...
6
votes
1answer
213 views

4X10GB Bonded NIC - only producing 4-5GB throughput

I have Two HPBL685c G6 blade servers running Ubuntu 15.04 Each server has 4X10GB NIC 2x10GB NIC are connected to a single VirtualConnect 10/10G Ethernet module The other 2x10GB NIC are connected to ...
0
votes
1answer
24 views

Is “'Light-Speed' Disk Access” really a thing? [closed]

I just saw an advert for Hyve hosting on You Tube. One statement made me curious, they said they offer "'Light-Speed' Disk Access": Is this just a fancy way of saying they have optical technology, ...
0
votes
1answer
138 views

OpenZFS on OSX filesystem dataset performance issue

tl;dr - My ZFS RAIDZ2 array reads at 7.5+ GB/s and writes at 2.0+ GB/s when I specify a bs=128K or greater with dd. OS X is assuming 1K (as per stat -f %k .) and all my is ~300MB/s; dd gives the same ...
0
votes
0answers
31 views

Azure ASP.NET website http requests queued

We have a website deployed on Azure that has dreadful performance. When load increases, response times increase to whole minutes! CPU load is not even high, somewhere in the 40% region (we run one ...
0
votes
2answers
43 views

I/O and RAM limitations are important for Hadoop performance. But is disk speed related to I/O?

Hortonworks says this: "Most often performance of a Hadoop cluster will not be constrained by disk speed – I/O and RAM limitations will be more important." * How is disk speed not related to I/O ...
0
votes
1answer
47 views

Why can I copy a file faster over the network than file to file on my SSD drive?

Dell Server running 2012 R2 w/ SSD's, Dell workstation running Win 8.1 w/ SSD's. I wanted to make a copy of a vmhd file so I just did a local copy/paste on the disk where the vmhd file was. When the ...
4
votes
1answer
51 views

Set USB HD to Better Performance on Windows Server Core

I have a USB hard drive plugged into a server running Windows Hyper-V-server, which in many respects is like Windows Server Core in that it has no GUI and no way to get to device manager. On a normal ...
3
votes
1answer
166 views

Qemu+libvirt+kvm significant performance lag in VM's

I am troubleshooting poor performance on our new VM host machine which is a Dell PowerEdge R415 with hardware RAID. We've got about 20 VM's running like this: qemu-system-x86_64 \ -enable-kvm \ ...
3
votes
2answers
164 views

How to optimize Apache speed for serving static content?

I'm well aware ngix is much better for static content, but I can't use it. Otherwise I have full access to my server (VPS). I've found numerous articles and posts about optimizing apache, but it's ...
1
vote
1answer
80 views

Benchmarks for server response time [closed]

I was testing my website’s performance on Google Page Speed and it mentioned the response time at It average between .6-.8 seconds. What’s the optimal server response time that’s acceptable? Is ...
0
votes
0answers
32 views

Something like Receive Segment Coalescing for UDP

The TechNet page on RSC states: RSC is defined only for TCP connections. RSC does not work with User Datagram Protocol (UDP) and other transport layer protocols. This is of course ...
6
votes
1answer
168 views

Is it possible to process millions of datagrams per second with Windows, using a vendor agnostic API? [closed]

I am investigating if I can implement an HPC app in Windows that receives small UDP multicast datagrams (mostly 100-400 Bytes) at a high rate, using a dozen or up to maybe 200 multicast groups (i.e. ...
6
votes
2answers
549 views

does adding heaps of drives to a raid 0 increase performance?

does adding heaps of drives to a raid 0 increase performance? i know that two drives in a striped raid will usually be faster than a single drive but will i notice a difference in performance between ...
12
votes
0answers
225 views

Why higher await time for DM multipath device than underlying device?

We have a CentOS 6.4 based server attached to Hitachi HNAS 3080 storage and observed the kernel remount the filesystem in read-only mode: May 16 07:31:03 GNS3-SRV-CMP-001 kernel: [1259725.675814] ...
1
vote
1answer
42 views

Application Performance & Interrupt Affinity

Quoting the RedHat Performance Tuning Guide 3.3.7. Setting interrupt affinity Interrupt requests have an associated affinity property, smp_affinity, that defines the processors that will ...
2
votes
1answer
81 views

Is there a maximum 'anything' when running a high number of processes on Windows

I have a series of well optimised services written in house using .Net running on many 512GB RAM server (a mix of Xeons including E5-2697 V2 etc). Is there a maximum handle, process, thread count that ...
2
votes
1answer
34 views

Does SAS server rotate always in it's default speed (like 10K, 15K)

I have some concerns about disk throughput in order to plan my SQL Server deployment. I know from experience that consumer SATA disks sometimes go into sleep mode when not used for a longer period. Do ...
16
votes
1answer
248 views

Vendor whitepaper says: 5Mpps no prob. I'm already hitting a wall at 120kpps. Where's the bottleneck?

HP's whitepaper on their QLogic (fka Broadcom) NetXtreme II adapters, which includes the specific NIC that I'm testing, states (page 7) that their small packet performance for packets up to 256 ...
2
votes
1answer
115 views

How much of a performance does using QEMU virtualization incur on Windows?

How much of a performance does using QEMU virtualization incur on a Windows host, when both the host and vm are running the same CPU? Older articles indicate that using kqemu avoided the slow down in ...
5
votes
2answers
234 views

raid controller data transfer rate

I'm going to buy an 8-port raid controller for which the declared data trasfer rate is "Up to 6Gb/s per port". The declared connectors are "Two mini-SAS SFF8088". The maximum number of supported ...
1
vote
0answers
45 views

Windows Server 2012 Disk Operations Freezing

I've got 2x brand new Windows server 2012 R2 servers. Fresh install. All Windows updates applied. One on a brand-new physical server, and the other in our VMWare cluster. When I try and perform a ...
2
votes
1answer
61 views

SAN performance too low?

I've noticed my new EMC VNX5200 SAN tends to perform better after "burning in" a partition. By this I mean filling the partition with different junk data and deleting everything a few times. Asked my ...
8
votes
2answers
617 views

Extreme UDP packet loss at 300Mbit (14%), but TCP > 800Mbit w/o retransmits

I have a linux box I use as the iperf3 client, testing 2 identically equipped Windows 2012 R2 server boxes with Broadcom BCM5721, 1Gb adapters (2 ports, but only 1 used for the test). All machines are ...
2
votes
1answer
95 views

Are RAID 5 systems suitable for larger disk sizes?

Why is it generally considered that RAID 5 systems are not suitable for larger disk sizes? Is the same true for RAID 6?
-2
votes
2answers
186 views

Why sometimes AWS EC2 works really slow?

I do only one thing one this server - encoding videos by ffmpeg. And sometimes it does work ok, sometimes it's really slow. I run the same command just for a test: $ sudo time ffmpeg -i test.mp4 ...
1
vote
0answers
50 views

File IO being slow

I've rented this root server with a RAID1 mdadm software raid setup. Using dd to benchmark the file IO speed it achieves 230MB/s write (default blocksize). Certain tasks such as mysql are way slower, ...
12
votes
4answers
337 views

tcpdump increases udp performance

I'm running a set of load tests to determine the performance of the following setup: Node.js test suite (client) --> StatsD (server) --> Graphite (server) In short, the node.js test suite ...
2
votes
2answers
69 views

Postfix long dns queries

I use my postfix server as a relay to another provider. I dig a little to find out why sending a simple mail takes so much time. I figure out that postfix do complete DNS queries for each single mail ...
-3
votes
1answer
834 views

Mysql showing 100% CPU usage [closed]

I'm experiencing some problems with my MYSQL server installed with Cpanel. My server is showing 100% usage of mysql even if I don't have too much traffic on web. I am running CentOS 6.5x64 with 80GB ...
0
votes
1answer
140 views

Ubuntu Trusty: virt-manager performance over WAN… 40+ secs freezes

I'm using the virt-manager GUI 0.9.5-1ubuntu3 on my laptop running Ubuntu 14.04 against a server located some distance away (same OS) and getting rather unpleasant performance. Laptop-server pings ...
0
votes
2answers
54 views

Same number of clients - multiple WAPs vs Single WAP

We purchased a device that acts as a WAP through which you can connect a mobile device and share its content onto a projector or tv. My question is - if we have multiple deployments of this device, ...
1
vote
1answer
33 views

server connection speeds can the be judged by a online speed test [closed]

Im currently investigating some issues on my windows servers. Ive run a test from my hosting provider and I think its incredibly slow. I've also run the same test but from my amazon AWS box and ...
3
votes
4answers
298 views

What is a core, and will purchasing more cores for my VPS speed up page load times?

I recently purchased a premium WordPres plugin called Hide my WP. I planned on using this plugin for my nonprofit organization's website, which is a multisite WordPress installation with an SSL. ...
1
vote
0answers
137 views

How do I interpret a very high Avg. Disk sec/Write perfmon value?

Short version: Is the perfmon screenshot shown below enough evidence to say "something is wrong with your storage system"? Long version: I am debugging a performance problem: Some SQL Server query ...
20
votes
5answers
5k views

Software vs hardware RAID performance and cache usage

I've been reading a lot on RAID controllers/setups and one thing that comes up a lot is how hardware controllers without cache offer the same performance as software RAID. Is this really the case? I ...
0
votes
2answers
37 views

MyISAM Throughput spike at 12000 record insert

I am testing database performance with bulk record inserts. Both systems are identical apart from storage engine **Database 1000 4000 12000** MySQL_InnoDB 60.95330976 ...
4
votes
2answers
793 views

Samsung 850 EVO + HP P410 limited iops?

I´m experiencing a weird write iops limitation with a HP P410 256mb cache controller and 4x consumer grade ssd´s (Samsung EVO 850) in RAID5/10. After upgrade to latest firmware (6.64) for HP P410 ...
7
votes
1answer
153 views

What do users see when Apache reaches MaxClients?

Occasionally, in my Apache error log, I will find: [error] server reached MaxClients setting, consider raising the MaxClients setting I've purposely lowered MaxClients in the past (to 60) due to ...