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4
votes
1answer
217 views

What is the size of an IO Operation (IOP) in AWS EBS?

My research suggests that both the standard and the maximum (kernel limitations) block size for modern file systems (ext4, xfs) is 4KB. However, AWS allows IO operations as large as 256KB and says ...
0
votes
1answer
19 views

What is counted as an I/O Operation?

What is counted as an IOP? Is one IOP one file read or written or one block (e.g. 4KB) read or written? Or something else?
0
votes
0answers
62 views

What would happen if I provision IOPS in RDS on a non-PIOPS-Optimized instance type?

Quote from the docs: If you are using Provisioned IOPS storage, we recommend that you use the db.m3.xlarge, db.m3.2xlarge, db.m1.large, db.m1.xlarge, db.m2.2xlarge, db.m2.4xlarge, ...
1
vote
0answers
31 views

“Hot data” and erasure coding: how to know if it is efficiently handled?

It is well known that erasure coding adds extra complexity because of encoding and decoding operations. Due to this drawback, most of cloud services recommend to use data replication for hot data and ...
-1
votes
1answer
38 views

How to specify the path which is to be tested using iozone?

I have a freebsd install which has ufs filesystem. Inside freebsd i have created a zpool in raidz1. Now i want to perform iozone test on zfs but i am not able to understand how to specify that iozone ...
3
votes
1answer
568 views

Will a SSD storage perform like a magnetic for small root volumes in AWS EC2?

I have a t1.micro instance with 8GB of magnetic EBS volume as it's root disk with a LAMP environment on it. I thought that I will upgrade it to t2.micro with 8GB of General Purpose SSD volume. ...
1
vote
1answer
150 views

Limiting - IOPS in VMware causing servers to run VERY slow

I have servers running a few different iSCSI SAN units. I was trying to balance IO requests to the datastores, so I started changing the "Limit - IOPS" on my servers from unlimited to 100-400 ...
0
votes
2answers
81 views

Measuring disk usage

What is the fairest unit to determine the disk usage (except the total storage usage e.g. in GB)? IOPS? Bytes read / write? Bytes transferred over network (would be equal to Bytes r/w)? Other? And ...
0
votes
0answers
86 views

XenServer IOPS read

I'm trying to retrieve some performance statistics from several Citrix XenServer installations (with versions from 5.5 to 6.2). What I need exactly are IOPS (read and write). Trying to use iostat on ...
12
votes
7answers
1k views

How do storage IOPS change in response to disk capacity?

All other things being equal, how would a storage array's IOPS performance change if one used larger disks. For example, take an array with 10 X 100GB disks. Measure IOPS for sequential 256kb block ...
1
vote
1answer
85 views

Many writes IO/s in Centos 6.5 - reverse ratio from read - as is normal

We have many CentOS6.5 servers on ESXI5.5. Storages for vmdk is SAN ISCI. I have problem with bad ratio for write/read. On storages I have about 2500 write io and e.g 200 read! For all time in day. ...
0
votes
1answer
233 views

IOPS bottleneck in design? [duplicate]

I'm building a 45 drives (backblaze) storage pod for use with Windows 2012 R2 Storage spaces. Spec is 2xE5-2620 v2 cpus, 32 GB ram, 3xLSI 9201-16i cards, 9x1 TB SATA SSDs, and 36x4TB HGST ultrastar ...
-2
votes
1answer
108 views

less IOPS number but better READ/ WRite performance [closed]

I tried measuring virtual disk performance using bonnie++. Case 1 result : Using uid:0, gid:0. Writing intelligently...done Rewriting...done Reading intelligently...done start ...
1
vote
1answer
719 views

Does ZFS really stripe across every vdev, even in very large zpools?

I have read that ZFS stripes the data in a zpool across all top-level vdevs, assuming all vdevs are added at the beginning of the pool's life. Everything I have read seems to regard this as a good ...
1
vote
1answer
435 views

Getting IOPS of the processes on Linux

So, what value should we read to get the in out operations per second per process? I've tried /proc/[pid]/io which returns these values: root@node:~# cat /proc/31597/io rchar: 213260190 ...
0
votes
1answer
2k views

Amazon: How do I know if I need Provisioned IOPS?

We recently moved to Amazon Web Servers and are still learning our way around. Our EC2 Web instance and our RDS MySQL instance (right now we only have 1 of each) seem to be chugging along okay. But I ...
0
votes
2answers
78 views

IOPs usage In HP Fata Disk Group VMware 5.1

We have a Blade with EVA storage array with 3 disk groups. One disk group consists of FATA 7200 1TB 18 hard drives, RAID 5, total IOPs 1000-1300. And I get statistics of used IOPs for this disk group ...
1
vote
1answer
638 views

interpreting IOPS these Bonnie++ and iostat results

I am looking to interpret the IOPS from a few runs of bonnie++ using iostat simultaneously and using the benchmarking from this post: Can I determine IOPS on a disk array using bonnie++? bonnie++ ...
1
vote
0answers
70 views

Upgrade the storage and/or provisioned IOPS on a reserved RDS instance?

I would like to reserve an RDS instance, but as of right now my instance does not need a lot of storage provisioned. I would like to reserve the instance with 100GB and 500 IOPS provisioned, but I ...
0
votes
0answers
102 views

confused by iostat reporting striped mdadm more tps than aggregate volumes

I've got an mdadm striped device (/dev/md0) from /dev/sdm{1..4}. Here is an output of iostat 30 and then mdadm --detail on the mdadm device # iostat 30 Linux 2.6.32-309-ec2 (ip-xx-xx-xx-xx) ...
-1
votes
1answer
126 views

How to test is hardware ssd-cache work?

We have server with hardware raid controller (Adaptec ASR71605Q). It has 10 sas HDD, 2 SSD for cache and 1gb onboard cache ram. On server installed ESXi. On ESXi I'm start Linux, create 2Tb disk for ...
4
votes
1answer
330 views

ESXi 5x: Changing number of IOPS per path sees dramatic improvements

I'm a bit embarrassed that I've never seen or used the -iops parameter as part of the esxcli deviceconfig options. I stumbled upon an article and proceeded to benchmark before and after using various ...
4
votes
1answer
371 views

How to calculate the required EBS PIOPS for our mongo server?

We want to use provisioned IOPS EBS volume on our mongo machines, I'm a bit confused on how to calculate the number of provisioned IOPS to use. Currently we're getting an average of 25 IOPS (read + ...
6
votes
2answers
3k views

Relation between disk IOPS and sar tps

I'm trying to estimate IOPS requirements of my application running on 32-bit CentOS 6.2. I started to take some measurement on a machine with SATA disks and I'm quite confused of difference between ...
1
vote
2answers
172 views

Calculating IOPS for a single HDD - what am I doing wrong?

So I know there is no standardized way of calculating IOPS for a HDD, but from everything I have read it appears one of the most accurate formulas is the following: IOP/ms = + {rotational latency} ...
3
votes
1answer
2k views

High iowait for unknown reason

I'm having a hard time figure out the reason cause high iowait on my server. This is log of iostat -xm 5 5 Linux 2.6.32-358.6.1.el6.x86_64 (prod-1.localdomain) 09/28/2013 _x86_64_ (16 CPU) ...
-1
votes
2answers
173 views

Raid0 IOPS poor performance [closed]

I've set up 8x500gb disks in raid0 on an EBS optimized EC2 instance and I ran iops.py to check the speed, but it seems really slow. Does anyone know if this is normal speeds for raid0? I'd think I'd ...
6
votes
2answers
3k views

Can I determine IOPS on a disk array using bonnie++?

I would like to measure the read and write performance of a RAID6 array verses a RAID10 array. I understand that bonnie++ can be used to calculate disk performance, but the numbers produced by ...
3
votes
1answer
2k views

Find current IOPS usage of EBS volume from my application on AWS EC2

I am relatively new to AWS and disk performance. I am trying to figure out how much provisioned IOPS does my application need to perform well. Currently My PHP and MySQL application is hosted on EC2 ...
1
vote
1answer
469 views

IOPS write increased, Disk write latency decreased, Avg req size decreased - Page load speed decreased

I have noticed decrease in server performance (page load speed become lower), then I went to investigate and have found in munin graphs (which tracks server's resources) that there was big changes on ...
3
votes
1answer
3k views

Why does storage's performance change at various queue depths?

I'm in the market for a storage upgrade for our servers. I'm looking at benchmarks of various PCIe SSD devices and in comparisons I see that IOPS change at various queue depths. How can that be and ...
1
vote
1answer
264 views

PHP Websites: Very high IOPS

We are hosting a set of websites on VM Cloud. These sites were previously on a couple of dedicated servers but to enhance performance, we transferred them onto a Cloud environment. The Cloud has SSD ...
2
votes
2answers
584 views

How to determine IOPS needs after getting the Transfers/sec data?

Let's say that I have gathered Disk Transfers per second data for 2x24 hours period, i.e., instantaneous sampling of data every 15 seconds. What statistical analysis can/should I apply to the samples ...
1
vote
3answers
812 views

perfmon reporting higher IOPs than possible?

We created a monitoring report for IOPs on performance counters using Disk reads/sec and Disk writes/sec on four servers (physical boxes, no virtualization) that have 4x 15k 146GB SAS drives in RAID10 ...
2
votes
1answer
269 views

How to cut php-fpm IOPS

I have Amazon EC2 instance with NGINX + PHP-FPM (through socket) + APC. I see sth. like this in iotop on high load. Total DISK READ: 0.00 B/s | Total DISK WRITE: 0.00 B/s TID PRIO ...
3
votes
2answers
802 views

8Gb Fiber Channcel HBA vs. 10 Gb SPF+ Converged HBA

I am putting a Dell server together, more specifically R720. I have to select the correct Host Bus Adapter. This HBA on R710 will connect to a storage device. I am confused between these two: QLogic ...
1
vote
3answers
2k views

Throughput = BS * IOPS?

I've seen in many places that throughput = bs * iops should be true. For example writing at 128k block size to a SAS disk that can support 190 IOPS should give a throughput of ~23 MBps - 23.75(MBs) = ...
0
votes
1answer
2k views

Measuring IOPs and comparing with IOmeter

So I've got to somehow generate IOPs using some prehistoric metrics used in IOmeter (which can't run in a 64bit ubuntu environment) The settings used in IOmeter are: 16K block size, 75% read to 25% ...
0
votes
3answers
16k views

How to measure IOps one virtual machine on VMWare ESX?

How should I measure IOPS generated by a single Virtual Machine in VMWare ESX? Also what would be a normal amount of IOPS for a Windows XP virtual machine?
2
votes
1answer
965 views

Estimate the IOPS in RAID 10

According to http://en.wikipedia.org/wiki/IOPS For example SAS disks provide ~200 IOPS each. For RAID 10 consisting of 4 such disks. How much IOPS I could expect for that array? I would think it ...
1
vote
1answer
212 views

Tools for gathering metrics about physical environment for use in virtualization/cloud planning?

I'm looking for tools that will work on either Linux/Unix or Windows Server that for a given set of servers in an enterprise environent, will: Identify the server [via hostname, or some other unique ...
2
votes
3answers
3k views

Disk IOPS count in GNU/Linux

I can't find information about ways to count disk iops in GNU/Linux for some time period. I saw iostat, but I'm not sure it is right way. Also i need tool, that can count iops for all time since ...
6
votes
4answers
3k views

ZFS: Redistribute zvol over all disks in the zpool?

Is there a way in which ZFS can be prompted to redistribute a given filesystem over the all of the disks in its zpool? I'm thinking of a scenario where I have a fixed size ZFS volume that's exported ...
5
votes
7answers
2k views

setup lowcost image storage server with 24x SSD array to get high IOPS?

I want to build let's name it a lowcost Ra*san which would host for our social site the images (many millions) we have 5 sizes of every photo with 3 KB, 7 KB, 15 KB, 25 KB and 80 KB per Image. My ...
0
votes
1answer
372 views

Hard drives, how to calculate read and write speeds supported? [duplicate]

Possible Duplicate: dell 2T 7.2k nearline SAS 6Gbps- ingress/egress throughput I don't have access to machine/drive, but need to define specs to purchase one. What all things would it be ...
0
votes
3answers
842 views

dell 2T 7.2k nearline SAS 6Gbps- ingress/egress throughput

I would like to know, how to calculate sustained read and write speeds supported. I don't have access to machine/drive, but need to define specs to purchase one. What all things would it be ...
0
votes
1answer
1k views

SAN I/O is horrible

I've been testing a SAN with fibre channel disks and I get 500MBPS Writes 200MBPS sequential reads and about 5MBPS randon reads / 1000 IOps max. Any idea why reads are so much slower? It is a 3PAR SAN ...
4
votes
1answer
2k views

Estimate IOPS for an Amazon EBS volume using Windows PerfMon

I'm evaluating moving our aging infrastructure to Amazon's AWS and am trying to estimate costs. I know our current disk space requirements, bandwidth, and most of the other variables that will affect ...
1
vote
2answers
5k views

How to interpret iozone values

I ran a test to measure my I/O IOPS on Linux: iozone -s 4g -r 2k -r 4k -r 8k -r 16k -r 32k -O -b /tmp/results.xls iozone claims that output is in operations per second yet the numbers are too big ...
9
votes
2answers
6k views

Measuring IOPS in Linux

How would I find out how many IOPS my Linux system can handle?