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

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62
votes
23answers
94k views

How to copy a large number of files quickly between two servers

I need to transfer a huge amount of mp3s between two serves (Ubuntu). By huge I mean about a million files which are on average 300K. I tried with scp but it would have taken about a week. (about 500 ...
0
votes
1answer
2k views

Why is hash join slow in postgresql 9.1?

I transfered my DB from Postgresql 8.4 to new server with Postgresql 9.1. Size of DB is 9.9GB Data directory is situated on ssd 60GB disk. And server has 16GB RAM and 16 proccessor cores. But today ...
-2
votes
1answer
27 views

Find a load on my Web Server [duplicate]

As requested, I am asking the question here. Is there a way to find a load on my web application server without a load / stress testing? I have deployed my application in the Apache Tomcat server. ...
2
votes
1answer
47 views

Does SAS server disks 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 ...
-1
votes
1answer
47 views

Handling the potential risk of writing random bits to storage during power loss with RAID [closed]

Is it possible for a power failure to cause some part of a machine to write one or more random bits to a storage device? Someone proposed the following idea to address such a risk: create multiple ...
5
votes
0answers
839 views

Troubleshooting Redmine performance

I've got a Redmine instance (Bitnami Stack) that's unusually slow. Because I'm just trying to get to the bottom of this, I have some theories which I'd like to discuss here. So, if anybody has any ...
0
votes
2answers
84 views

Should I use a server to do multiple services [closed]

I want to ask, I want to build a DNS server, mail server, and DHCP server and possibly an SQL server in my office, the client to this server is less than 100. So, if I have a server, say, with RAM 12 ...
0
votes
1answer
2k views

Enable: Asp.net connection pool monitoring with performance monitor

I'm a C# developer, but I'm running in a system management issue here. Intro: I'm suspecting that an ASP.NET application is having some issues with the connection pool and that the pool is flooding ...
1
vote
0answers
31 views

How to compare and state performance on virtual server instance?

I want to report performance statistics about an algorithm that runs on a virtual server instance with Ubuntu on it. I measured runtime and maximum memory usage but I want to give a statement about ...
1
vote
0answers
109 views

LSI SAS1068E (aka LSI SAS 3442E-R) bandwidth

Recently I connected LSI SAS 3442E-R and two HP SAS 600GB 10k HDD. My motherboard is AsRock Z97 Extreme6. Disk are configured as JBOD, no raid. Linux lspci shows: 0b:00.0 SCSI storage controller: ...
2
votes
1answer
217 views

CPU is only used 50% on full load on a Windows Server 2012 R2 [closed]

I use Windows Server 2012 R2 on my home server (it's a mini-ITX PC based on an Asrock E350M1/USB3 motherboard, so it's not a strong enterprise server). My problem is that even when I run multiple ...
4
votes
2answers
484 views

Linux: Why does the CPU frequency fluctuate when using the performance governor?

I'm using a Debian 8 amd64 machine for benchmarking. During experimentation, I would like the CPU to operate at a fixed frequency (preferably the maximum possible). This will rule out the CPU clock ...
2
votes
1answer
435 views

Nginx performance when running multiple instances on the same machine

I'm trying to understand the performance impact of having multiple nginx instances (masters) running on the same machine, rather than having them all load into a single instance using different server ...
2
votes
3answers
167 views

Apache - drawback to high number of httpd processes always running

Is there any issue with having a high number of spare httpd processes always running? I ran a test where I increased StartServers and MinSpareServers by 1,000 and measured the increase in memory ...
3
votes
2answers
50 views

Can idle NFS mounts on several clients impact performance

We had a NFS server at work which was working with slight lag. However as more mount points were getting created at several clients(serviced by the same server) we noticed the performance coming to a ...
0
votes
0answers
44 views

The difference in performance of different memory mount in dell poweredge R430

There are 3 servers R430 (S1, S2, S3). All of them have 2 procesors and 8*8GB of ram in slots A1-A4 and B1-B4. There is a need of extending memory. I've read dell recomendations ...
5
votes
4answers
11k views

How do I configure RAID 5, especially stripe size, with 24 x 1.2 TB drives for CentOS 6?

For a Dell R920 with 24 x 1.2TB disks (and 1TB RAM), I'm looking to set up a RAID 5 configuration for fast IO. The server will be used to host KVM VMs that will be reading/writing files of all sizes, ...
0
votes
1answer
43 views

Is it bad to use swap with SSD when running a server out of memory?

I have DigitalOcean VPS, which has 2GB of memory. I'm soon running or am about to run out of it. How big is the performance hit if I use big swap? DO use SSD has harddrives, and I'm not the one who ...
1
vote
1answer
90 views

Slow file io performance after large network copy on Win7

In a step of our build process we run a tool that generates about 125,000 files. When generation is complete we copy them up to a network share so other systems can copy them down to process further. ...
1
vote
0answers
82 views

Redis parent process smashing disk despite appendfsync = no

We are seeing loads of IO from redis-server despite our save operations being set to occur once every 15 minutes only. The workload is a "full page cache"; we store blobs of compressed HTML. The HTML ...
3
votes
4answers
661 views

Azure IO performance

We have a number of Windows Server virtual machines that we use for .NET and Java development and QA. I find Azure attractive for the obvious reasons but mainly for the opportunity to reduce ...
2
votes
2answers
384 views

ZFS reads on FreeBSD incredibly slow

I have a FreeBSD 10.0 system on which I have MySQL running with its InnoDB database files stored on ZFS. It seemed to have been going fine for months, but lately, and seemingly suddenly, performance ...
1
vote
1answer
176 views

Debugging slow server response time [closed]

I'm testing response time of my VPS server: curl -s -w %{time_total}\\n -o /dev/null http://www.example.com The values are typically round 300ms, Google suggests that it should be lower than 200. ...
4
votes
0answers
136 views

HP MSA P2000 G3 Disk Scrubbing performance?

I have a HP P2000 G3 array with two 10Gbit iSCSI controllers in it that presents storage to my virtualisation cluster. It is soon to be expanded with two D2700 shelves each loaded with 25 10k RPM ...
7
votes
1answer
1k views

ext3 file system performance tuning: what metrics to monitor

I have a high-IO application that is working, and scaling well to date. Over the past few months we've been trying to look down the road and predict where our next bottlenecks will occur. One of ...
0
votes
0answers
70 views

apache 2.2 to 2.4 sporadic performance drop

I updated apache from 2.2 to 2.4 and php from 5.3 to 5.4. For some reason I am experiencing huge performance drops in around 5% of requests to the server. On average, sites load in less than 2 seconds ...
4
votes
3answers
3k views

How can I check if my DB needs more RAM?

How would you check if your postgresql DB instance needs more RAM memory to handle their current working data?
0
votes
0answers
14 views

Conservative Azure Windows VM to Run SQL Server 2008 R2 [duplicate]

For testing purposes I need to set up three Azure Windows VMs to each run an instance of SQL Server 2008 R2 each holding one DB of approx 100GB. There will be quite a few complex stored ...
0
votes
0answers
25 views

Performance monitors

I would need to create a performance monitor on windows server 2012 R2 to monitor the following for a particular period(may be one hour) CPU usage Memory usage Network bandwidth I'm little ...
15
votes
3answers
2k views

NFS poor write performance

I have two machines connected with 10Gbit Ethernet. Let one of them be NFS server and another will be NFs client. Testing network speed over TCP with iperf shows ~9.8 Gbit/s throughput in both ...
0
votes
0answers
45 views

Sudden increase in my CPU usage during random moments(Win Server 2012)

At random times, no matter if I am online or not I see that my server having increased Process usage spikes, as you can see in the picture: So I go inside the Dashboard on the Server Manager, look ...
3
votes
1answer
2k views

Very poor disk performance on KVM node - mdadm raid10

For a long period of time, i'm experiencing performance issues on CentOS servers that are used for KVM virtualization. I'm running software RAID-10 with 4 disks (Seagate ST2000DM001, 2TB, 7200rpm ...
4
votes
1answer
9k views

MySQL high CPU usage on small website

I have a small website hosted on a dedicated server (FreeBSD 9.2, MySQL 5.6.1 and php 5.5.5). The problem is that MySQL eats a lot of cpu resources even if the website have a few visitors. The ...
-1
votes
1answer
31 views

Is there a way to determine what impact an upgrade will make other than benchmarking it myself? [closed]

Several posts on capacity planning tells me that the only way for me to determine what hardware I need is to test it myself and benchmark it. Benchmark your code on hardware similar to what you'll ...
1
vote
0answers
195 views

VMWare ESXi and iSCSI via FreeNAS

I've recently been setting up a sandbox ESXi environment with a VM running FreeNAS providing a volume which is connected as a datastore on the host via iSCSI. I've created a VM on this datastore and ...
1
vote
1answer
41 views

RAID1 write penalty using mdadm - what's the cause?

When doing some performance tests writing to a SSD-based 3-way RAID 1 mirror powered by mdadm, it appears we suffer a significant write penalty of about 2.2x slower than doing the same test on just ...
18
votes
4answers
13k views

Why VM snapshots are affecting performance?

I read in one of the VMware KB articles that snapshots will directly affect VM performance. But my team keeps asking me how snapshots can affect performance. I would like to give them solid reason ...
5
votes
2answers
443 views

iozone: 5 concurrent threads random read of 300K blocks does more ops/s than using only one thread, what could be the underlying reason?

The partition is in RAID1 using software RAID. Command line used: iozone -s 190g -r 300k -O -b test_file OPS Mode. Output is in operations per second. ...
1
vote
2answers
527 views

Can one root server handle over 50M requests per month? [duplicate]

I am running a LAMP Application installed on one server, happily serving about 1M PI per month. Now I am looking into a potential partnership where my app might serve around 50-80M requests per month. ...
3
votes
2answers
240 views

Performance azure disks, high average queue length

I'm having a classic developer-system admin battle where I am stating that there is an IO problem on the disk of the shared sql server while the system admin tells me that the capacity hasn't been ...
1
vote
0answers
141 views

100% CPU, load average 0 - how is this possible?

Here's the top output: top - 19:20:47 up 1 day, 4:30, 1 user, load average: 0.01, 0.07, 0.12 Tasks: 170 total, 1 running, 169 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.6 us, 0.9 sy, 0.0 ...
3
votes
4answers
2k views

How to troubleshoot performance issues of PHP, MySQL and generic I/O

I have a WordPress based website running on a shared hosting. Its response time is very decent (around 2s to retrieve the HTML page and 5s to load all the resources). I was planning to move it to a ...
26
votes
5answers
15k 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 ...
1
vote
0answers
19 views

Force disk cache even if guest uses direct i/o

Have IBM db2 on Rhel on Hyper-V on Windows Server. The *.vhdx file is on CSV. e.g. C:\ClusterStorage\volume1\hyper-v\oktest-lb1\oktest-lb1.vhdx. db2 uses O_DIRECT flag (uncached i/o) for its database ...
1
vote
1answer
44 views

Different network speeds from servers on same subnet

I have a pretty strange issue, I'm looking for advice on how I can debug it. I have two servers (A) and (B) on the same subnet and switch. Server A->B transfers at a full 12MB/s and vice-versa. ...
1
vote
0answers
43 views

How to track down bad performance on an api-server

If my api-server shows bad performance, such as high cpu - can this be blamed on the service or on the server? If a regular app-server shows bad performance, all I can do is track down the methods ...
0
votes
0answers
23 views

SSD vs RAM - Optimal ratio for different data sets / databases [duplicate]

I am looking for an advice or even better some studies / benchmarks to read for different scenarios (data sets) when it comes to the best ratio between actual RAM and SSDs. I know that fitting the ...
0
votes
0answers
158 views

vSphere | VMs are balooning and swapping | sched.mem.max paratmetar does not exist

I have two VMs in ESXi5.5 environment that are swapping memory. After a long research I found out the below two articles where it is explained that one must compare the values of memsize and ...
2
votes
2answers
104 views

Migrating Vmware to Hyper-V - number of Virtual CPU

I'm performing a migration from VmWare to Hyper-V and the Virtual CPU that you are assigning to a Virtual Machine is different and I'd like to know what should be the equivalent values when we move a ...
0
votes
0answers
56 views

How can I adjust buffer settings when using xbootmgr?

I am trying to analyze our clients which suffer from long boot & logon delays, so I installed Windows Performance Toolkit. This is the command line I have used to capture a startup: xbootmgr ...