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

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15
votes
2answers
29k views

Best Mysql cache settings for 8gb RAM dedicated mysql server using only Innodb (5gb database)

I'm a pretty big noob when it comes to setting up mysql for performance. And honestly I'm not worried about the fine tuning to squeeze every last bit of performance out of mysql, but I do know that ...
2
votes
1answer
57 views

Why might 'mpstat' and 'pidstat' disagree about CPU load levels?

I'm monitoring a mysql process in ubuntu 12.04 using mpstat and pidstat, simultaneously. While debugging its CPU usage, I noticed something unusual. While both tools agree that CPU load is occurring, ...
1
vote
2answers
1k views

Troubleshooting MySQL Performance Issues

Environment: 1 physical machine 8GB RAM some older Core2Duo CPU 1 HDD Windows Vista 64 bit 1 Virtual Machine 16 GB RAM 2 vCPUs Windows 7 64bit Both machines running MySQL 5.5.28 (64Bit) with ...
18
votes
11answers
10k views

Are there any good reasons for disabling hardware-assisted virtualization?

We've had a number of servers from Dell recently, all of which have had hardware-assisted virtualization disabled in the BIOS. As far as I know hardware-assisted virtualization is a good thing - so ...
3
votes
2answers
708 views

Performance associated with storing millions of files on NTFS

Does anyone have a method / formula, etc that I could use - hopefully based on both current and projected numbers of files - to project the 'right' length of the split and the number of nested ...
-1
votes
1answer
38 views

Which raid array will be best practices with seven 1.2 tb hdd system

I have a server which have seven 1.2 tb hard disks. I have to create raid array but i don't decide which raid i use? First of all, first and most important matter is security. At any cost i must not ...
0
votes
1answer
15 views

Increase openfire memory to larger values

We use OpenFire for XMPP messages. We have some memory issues(OutOfMemoryError), and therefor we would like to increase memory. I know how to increase memory using VM options and we were able to ...
0
votes
0answers
25 views

lower tcp throughput than expected

I've conducted some tests which measured tcp throughput via wireless and wired connection. (a) was wired link between my desktop and my home router. (b) was wireless link between my desktop and my ...
0
votes
0answers
31 views

Reduce Connecting time to server for inital request

I am struggling with decreasing load time of inital html page request. It is consistently above 800 ms however other websites they load in less than 300 ms. In this load time GTMetrix shows more than ...
0
votes
0answers
19 views

Does decommissioning nodes on hadoop cluster hamper performance?

I have 120 node Hadoop cluster, I have removed around 14 nodes in 7 days (each day - 2 nodes were decommissioned) Now users are facing some performance issues, does this decommission really matters. ...
0
votes
2answers
1k views

RAID1 very slow with LSI card and 2x Samsung EVO 850 drives

not sure if I'm checking it correctly, but here is what I have. Desktop, LSI 9260-8i card, see config below. 2x 500Gb Samsung 850 EVO drives. I also have Samsung 830 drive attached to motherboard ...
0
votes
1answer
25 views

Speed: nginx serving static content even faster: fixed folder ; how can I

we run centos and nginx one of latest versions in 2016. We use 1 media directory with some underlying subdirectories. FTTB for php is 200ms which is very fast - but now I discovered that the JS CSS ...
1
vote
1answer
64 views

Hardware performance penalty for Hyper-V Generation 2 VMs

I have the following configuration: Windows Server 2012 R2 OS installed on baremetal with Hyper-V. OS is installed on RAID1 850 PRO drives. Windows Server 2012 R2 Guest OS Generation 2 VM is located ...
1
vote
0answers
49 views

Slow gigabit speeds with Ookla speedtest software

We have 2 speedtest servers (RHEL 6.7) sitting on 10GB links with a 10GB pipe between the two. The servers are separated geographically by about 256 miles but traceroutes look very good, with 4 hops ...
6
votes
2answers
227 views

Odd performance fluctation with php-fpm and nginx

I'm running a load test against a web service. It's a php application running on php-fpm and nginx, with fastcgi. There is a MySQL backend being used for small reads only. Invariably, I'm seeing a ...
0
votes
0answers
23 views

Real memory usage on Linux and Private_Dirty

On Linux, is using Private_Dirty value from smaps a good way to measure real process memory usage? Thanks
3
votes
2answers
604 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 \ ...
0
votes
0answers
46 views

Disk performance drops in VMWare ESXi 4.1 / 5 Linux Guest

I'm benchmarking disk write performance using this command: dd if=/dev/zero of=/mnt/test.dmp bs=1M count=256 conv=fdatasync After a random time and random number of attempts, the file system ...
2
votes
1answer
65 views

Is this btrfs snapshot removal performance normal?

I have several boxes running Debian 8, dovecot and btrfs. I'm using btrfs snapshots for short term backup. For this purpose I keep 14 snapshots of the mail subvolume. Performance is OK until it comes ...
0
votes
0answers
21 views

Why in my index in a cold situation that slow?

We have a table CREATE TABLE mytable ( ... myfield bigint, ... ) and an index CREATE INDEX fk_fk18edb1cf49a32f88_idx ON mytable USING btree (myfield); and a simple query SELECT count(*) ...
2
votes
3answers
14k views

How to get more I/O performance from Citrix XenServer?

I have a Citrix XenServer 6.1 installed on a HP Server (1x Intel Xeon E5630 @ 2.53GHz (4 cores, 8 threads, RAM: 752MB for dom0 and 55286MB for the guests). The server has 2 scsi mirrored disks and is ...
4
votes
2answers
15k views

Poor Disk Performance on VMs; Host using PERC H310 RAID 5

I have a Dell R620 running 5 500GB 7.2K RPM SATA 3Gbps 2.5in Hot-plug Hard Drives in a PERC H310 controller (which I am beginning to regret buying). I am getting awful read/write speeds on Linux ...
1
vote
0answers
23 views

iperf actual send rate always lower than the expected target bandwidth until some equilibrium reached. Why?

I did an UDP iperf 2.0.5-Ubuntu test between two VMs on the same hypervisor. As can be seen in the iperf output below I started my first test with "-b 686M" flag. However, iperf reported that it was ...
1
vote
1answer
36 views

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 ...
1
vote
3answers
106 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 ...
2
votes
1answer
37 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 ...
1
vote
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 ...
1
vote
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 ...
0
votes
0answers
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 ...
5
votes
7answers
32k views

Windows networking performance (SMB/CIFS)

Are there registry settings or other settings available to tune Windows networking (SMB/CIFS) performance? I'm trying to get maximum throughput for large file copy operations but any settings would ...
0
votes
0answers
44 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 ...
1
vote
0answers
34 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 ...
-1
votes
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 ...
1
vote
2answers
47 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: ...
15
votes
8answers
10k views

How to scale php5+MySQL above 200 requests/second?

I am tweaking my homepage for performance, currently it handles about 200 requests/second on 3.14.by which eats 6 SQL queries, and 20 req/second on 3.14.by/forum which is phpBB forum. Strangely ...
3
votes
1answer
85 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, ...
11
votes
1answer
242 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 ...
0
votes
0answers
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 ...
0
votes
0answers
56 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 ...
3
votes
3answers
10k views

How do I identify slow queries in sql server?

I've found long, complicated instructions like this when googling for the answer to this question, an brief reference links such as in this post. I'm looking for a succinct a procedure as possible to ...
1
vote
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 ...
0
votes
1answer
235 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. ...
1
vote
2answers
1k views

How efficient is iptables' hashlimit module?

I'm looking for a solution to rate-limit on an ip basis. How many packets can the hashlimit iptables module handle on a recent Intel x86_64 CPU core? 1.000/sec? 1.000.000/sec?
0
votes
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 ...
2
votes
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 ...
1
vote
2answers
2k views

MySQL high “sy” (kernel) CPU time

My MySQL server runs about 100 writes and 500 reads per second. The CPU usage looks strange to me. "us" (user) time shows 2-8%, while "sy" (kernel/system) time often shows 50+%. Here's some vmstat ...
15
votes
4answers
20k views

How can I find out what is causing interrupts on Windows?

Occasionally I come across servers (Windows 2003 and 2008) with high processor % interrupt time. Is there a way to see what program or device is causing the interrupts?
0
votes
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 ...
3
votes
2answers
566 views

optimizing ext[234] for small file throughput

I have a system that has a high throughput of small files on disk, i.e. a huge number of small files are created, written and deleted within seconds. Are there any reasonable ext2/ext3/ext4 mount ...
2
votes
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 ...