Questions tagged as ['performance']

Questions about server hardware and software performance, or network performance.
Score: 2
High speed network writes with large capacity storage
pf flag

I have a NAS running Samba with a 20T ZFS pool with one raid1 vdev with two spinning rust drives. I have 16G RAM in the machine right now. The storage is used for continuously growing, permanent backup archive of video footage. It's write once, read once for processing and then possibly backup restore.

I regularly fling 40GiB files to this NAS. I'm going to upgrade my gigabit network to 10GbE in  ...

Score: 0
biwiga avatar
Apache crashing because of high memory usage
th flag
  CPU[||||                                                    3.3%]     Tasks: 71, 155 thr; 1 running
  Mem[|||||||||||||||||||||||||||||||||||||||||||||||||1261/1875MB]     Load average: 0.00 0.02 0.01 
  Swp[                                                       0/0MB]     Uptime: 02:17:35

  PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command
 2385 centos     20   0  110M  2136  1228 R ...
Score: 0
How to increase the block size of an ext4 filesystem beyond the 4KB limit?
es flag

Is there a way I can increase the blocksize of my filesystem (ext4) beyond the 4KB limit?

I want to increase the random read/write speed of my filesystem by increasing the block size but I can't go any further than the page size. Is there a way to work around this?

I would appreciate any instructions or help to make this change. Thank you.

Score: 2
J.D. avatar
How to debug the cause of my suddenly extremely slow running database backups maintenance plan?
sa flag

(Originally posted on but closed, hopefully more relevant here.)

Alexander and the Terrible, Horrible, No Good, Very Bad...backups.

The Setup:

I have an on-premise SQL Server 2016 Standard Edition instance running on a virtual machine from VMWare.


Microsoft SQL Server 2016 (SP2-CU17) (KB5001092) - 13.0.5888.11 (X64) Mar 19 2021 19:41:38 Copyright (c) Microsoft Corporat ...

Score: 2
roee klinger avatar
How to scale OpenVPN when client-to-client is a must?
bd flag

I am trying to create an OpenVPN server cluster that can autoscale, I have found a lot of information online on how to create such a network.

As far as I understand, you basically use a round-robin DNS, and few OpenVPN servers, the clients simply connect to the DNS and are assigned one of the OpenVPN servers to connect to.

However, my setup requires that all clients will be visible to each other, so ...

Score: 0
Zoro Steve avatar
Disk IO issue with high Page writeback
us flag

I have been trying to figure out what's going on with some of our servers. These are KVM hosts that have 5 -8 VMs. RAM >= 64GB, 10 - 20 cores. These are running Ubuntu 18.04 LTS 4.15.0-142-generic Kernel, LUKS encrypted ext4 root partition.

Randomly, some of these servers will become very slow. All indications would point to Disk IO, but really there isn't much workload consuming IO (pidstat,  ...

Score: 0
a b avatar
High CPU usage by Apache/MySQL
cn flag
a b

I have a problem with CPU usage on the website that uses WordPress, Apache, and MySQL. During the day, from time to time, CPU usage by MySQL and Apache goes up to 2400% (I have 24 cores in total), the server freezes, the average load goes up to 24.

Recently, there was a little more traffic than usual, but this thing shouldn't be permanent, right? I've updated the kernel, the database, libraries,  ...

Score: -1
Ali Eb avatar
8 x 15k SAS hdd disk with raid 0 performance vs single SSD disk for database
jp flag

Which one has a better performance for database application (e.g. postgres) if we just consider read/write operations speed and not fault tolerance

  • 8 x 15k SAS hdd disk with raid 0
  • single SSD disk
Score: 0
Poor disk throughput on Google App Engine
tc flag

Is there any way to manually provision IOPS for the disk used by the instances on Google App Engine?

The default throughput I get with a 256GB disk is terrible (60MiB/s burst, after which is settles to 30MiB/s combined for reads and writes).

Is there an option in App Engine to:

  • Provision IOPS manually
  • Use an SSD
  • Use a VM instance template so I can configure the hardware template in Compute Engine a ...
Score: 0
David Chiang avatar
Some process are in unkillable sleeping state while i/o is low
es flag

I am the system administrator of an Arch Linux-based workstation. Our workstation uses Slurm as the load manager and consists of one master machine and 4 other computation nodes. In the past few months, we observe that processes on some nodes are stuck from time to time, and rebooting the node solves the problem. We found that the stuck processes are in state D (disk sleeping), but when we use top or ot ...

Score: 0
TCP Handshake and TCP RTT when using VPN
cn flag

From my server I'm measuring the TCP RTT and I was wondering what would be the difference between clients that use VPN compared to non-VPN clients.

So in the case of a non-VPN client the TCP session is established directly with the customer, which means that I'm actually measuring the RTT of the full path. What is happening with clients who connect through a VPN server?

Does the VPN server maintain  ...

Score: 0
Windows RAID drive performance suddenly dropped
ru flag

I have a Windows system that has as a data drive, one RR640L controller. Attached to this controller are four 2TB drives in a RAID5 configuration (2 Seagate ST2000VN000 and 2 Samsung HD203WI).

Suddenly, read performance from this (logical) drive has plummeted. This is the most-used drive, so the impact was noticeable immediately. Running a routine backup (just a robocopy to an 8TB SSD) I'm get ...

Score: 0
Holy_diver avatar
Cache Images centrally
ng flag

Application: Serve responsive and optimized images on the fly by cropping/resizing/compressing master images

Current Load: 10k request per minute, ~60MBps traffic.

Current Config : NginxPlus LB sits at the top. Multiple app servers with nginx->tomcat. On each app server images are cached in the nginx

Current Problems:

  • Poor cache hit ratio as cache is decentralized, probability of same request hitti ...
Score: 2
RHEL8: Does NFS I/O count as part of "%iowait" calculations?
in flag

Customer telling us that they see high %iowait in top and iostat output on a busy RHEL8 NFS client.

iostat man page clearly says that iowait is related to % of time kernel is waiting on "disk" I/O

Question - does NFS I/O count as "disk" I/O in %iowait calculations?

Score: 0
Sridharan Srinivasan avatar
MySQL - Select queries 10x slower on Azure VM vs on-prem VM
cn flag

We have been working on a project to migrate a MySQL database from an on-premise Linux server to a Windows VM on Azure (IaaS). (There's a specific reason because of which we have gone with the IaaS option instead of the Azure MySQL PaaS offering).

After the migration, we see that the queries on the MySQL database are significantly slower (about 10x) on the new server. The VM is configured with 64 ...

Score: 0
Speedtest website for google could storage, AWS S3 storage, Azure Blob storage
tr flag

Where could we find the website to perform speedtest for download/upload/lantecy for:

Google Cloud Storage AWS S3 Azure Blob Storage

There is one for B2, publicly. For wasabi, you need to contact the sales.

Score: -3
9mjb avatar
Is there a program to diagnose and summarize why my mchine is slow?
ru flag

Is there a program that will tell me why my server is slow? What is being over utilized? CPU / Memory / Disk / Network ... and what processes are driving that utilization? I want a program that can check and explain it to me. (I don't want to figure it out myself.) Maybe it could even suggest server tuning changes.

Score: 0
How to configure HAProxy to ignore client header `Pragma: no-cache`?
ve flag

We have a web service behind a HAProxy server running in caching reverse proxy configuration. The backend servers send Cache-Control headers correctly for all responses so HAProxy can cache all responses according to HTTP spec.

However, when the end user hits the Shift+Reload button in e.g. Google Chrome, the client (Chrome) sends Pragma: no-cache and Cache-Control: no-cache which forces HAProxy to a ...

Score: 0
How to toubleshoot poor IO performance on Windows Server
ng flag

I am experiencing poor write performance on my Windows Server 20H2 machine (ESXI 7.02). Following symptoms are observed on a docker build: Each RUN command executes successfully, though takes ~10 hours to move to the next command (committing on disk is slow). The same is about 2 minutes on physical OS, on exact same hardware.

My hardware configurations are as follows:

8 CPUs x Intel(R) Core(TM) i7-107 ...
Score: 0
How do I maximize nvme raid0(md) performance (in linux)?
tt flag

Nvme raid0 read(and write) performance is sometimes worse than the performance of one individual underlying drive.

hdparm -t /dev/md0 :

Timing buffered disk reads: 7054 MB in  3.00       seconds = 2350.46 MB/sec

hdparm -t /dev/nvme0n1 :

Timing buffered disk reads: 7160 MB in  3.00    seconds = 2386.32 MB/sec

This is a datacenter hosted bare metal unit, the drives and the server are cooled properly so t ...

Score: 0
Mukesh avatar
Less requests per second on Apache Bench test from same server
gt flag

I ran following test on one of my website from the server where it is hosted itself.

ab -n 100 -c 10

enter image description here

It serves very less number of requests per second.

The server configuration is 64GB RAM, 16CPU, Ubuntu20.04 and webserver is Nginx 1.14

When I run same test on a different website which is running on 8GB RAM, 4CPU, Ubuntu 18 and Apache2 webserver, I am getting the 20.09 requests s ...