The disk-performance tag has no wiki summary.
2
votes
4answers
104 views
What does “random seek time” really means in HDD benchmarks?
I am currently benchmarking a hard drive. I am using HW32 for the measurement.
The result has two parts:
random seek time: 20 ms
random read throughput: 30 Mbytes/s
I am not sure the methods HW32 ...
5
votes
1answer
207 views
HP DL380 G7 + Smart Array P410i + sysbench -> poor raid 10 performance (resolved!)
I have running system with low IO utilization:
HP DL380G7 ( 24gb RAM )
Smart Array p410i with 512mb battary backed write cache
6x SAS 10k rpm 146gb drives in RAID10
Debian Squeze linux, ext4 + LVM, ...
0
votes
0answers
27 views
Phenomenon when there is intensive I/O operation the whole system freezes?
I've payed attention to a pattern that I've observed though out the years on development machines (common hardware, Intel motherboards).
When I cause heavy I/O operations that whole system becomes ...
0
votes
2answers
30 views
How can I decide up the nature of performed IO?
I am using Linux (3.2.12-3.2.4).
I have few "syncer" processes which updates lots and lots SQLite db files in a loop. The database sizes vary from 1 MB to few GB.
I have a "searcher" process which ...
4
votes
2answers
63 views
Very active database with high % disk times
I have a very active website which is using a NoSql database (RavenDb). I don't have exact figures as i'm not quite sure how to extract this information (any help would be great!)
But looking in ...
0
votes
0answers
231 views
Proxmox, Windows and virtual disk cache modes
I run Proxmox 2.0, and installed Windows 2003 R2 (32-bit) server on it. I've use VIRTIO disk and NIC virtual devices (and installed appropriate drivers into Windows), and everything's fine. Physical ...
1
vote
1answer
78 views
Any performance difference to identical spec of LFF disks vs SFF disks?
Example:
HP 146GB LFF 6G SAS 15k
vs
HP 146GB SFF 6G SAS 15K
bit-size, cache, interface speed and rpms are the same, physical size is obviously different -- what about actual real life tested ...
1
vote
1answer
228 views
Poor Write Performance in VM inside Proxmox PVE 2.0
I am running a PVE 2.0 on a decent Hardware (2 SATA HDDs as RAID1, 12GB RAM, i7 CPU) but the I/O Performance is very poor inside the VM (Ubuntu 11.10 Server). The very same VM was copied to another ...
1
vote
3answers
163 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) = ...
5
votes
1answer
138 views
Win 2008 R2 - copying TO disk is very slow, copying FROM is more or less okay
I have Windows 2008 R2 SP1 with 4 identical SATA disks (Seagate Barracude 7200) in RAID 5 array. It has 4Gb of memory; all recent updates are installed. Problem: when I copy large file from one ...
2
votes
1answer
47 views
How can i view the disk latency of a ZFS pool, or of the disks in it?
I'm using FreeBSD. I would like to write a munin plugin to log it, but i don't understand how to get this data.
2
votes
3answers
139 views
Raid-5 Performance per spindle scaling
So I am stuck in a corner, I have a storage project that is limited to 24 spindles, and requires heavy random Write (the corresponding read side is purely sequential). Needs every bit of space on my ...
2
votes
2answers
74 views
Measuring I/O Performance Paradox
I'm trying to figure out the correct way to get the 'real world' write performance
of my NFS cluster.
The NFS export is mount on a XEN hypervisor, and I'm running 'dd' from within a VM.
What I ...
2
votes
2answers
124 views
Windows: How to determine the cause of heavy disk use
I'm using perfmon's "PhysicalDisk\% Idle Time" to determine when the disk is being used heavily. The question is, what's the best/quickest way to narrow down what was using the disk?
I'm aware of the ...
0
votes
0answers
148 views
Very bad performance of ext4 with kernel 3.0.17
I just set up a new server (Gentoo 64bit with kernel 3.0.17) with 4 x 15000RPM SAS disks(sdc, sdd, sde and sdf), and created soft RAID10 on top of them, the partitions are aligned at 1MB:
# fdisk -lu ...
3
votes
2answers
276 views
What could cause very slow (3 MB/s) disk access on a Ubuntu guest running under Hyper-V?
I have a Ubuntu 11.10 x64 guest running under Hyper-V on Windows Server 2008 R2 SP1, configured according to these directions, including installation of the hyper-v modules. Network speed is fine (500 ...
1
vote
1answer
82 views
Slow performance when serving files on Windows 2003 - where to search?
I've been searching for similar questions, but couldn't find any useful, sorry if duplicate.
(I read windows 2003 server slow access and Horrible Windows Server 2003 performance while copying files ...
2
votes
2answers
378 views
High disk I/O when cache is used?
A few days ago I noticed a disk I/O wait and disk activity drop (which was great). Then I also notice that my cache was full(*) and fragmented. Then I flushed cache. After that, disk latency and disk ...
0
votes
2answers
74 views
Disk Throughput Terminology
Imagine running a test where you have a network-attached storage device, and there are two running processes (on different machines), reading and writing the same file on the NAS. Process 'W' does ...
1
vote
3answers
103 views
8MB/10K RAID5 vs 2x 64MB/7.2K RAID10
I'm looking at replacing an old file server sharing a single RAID5 volume powered by 6 10K rpm disks with 8MB caches. The replacement will be 2 RAID10 volumes of 4 disks each. The new disks have 64MB ...
1
vote
3answers
76 views
Limiting specific process to just one per user
My scripts are using wget to retrieve data from Internet. When many users are using this script I got very high load (about 20.00), because of disk I/O. Wget is automatically started each hour by ...
2
votes
1answer
59 views
Filesystem speed shaper for Linux
There is an iprelay (or ip_relay) package to shape TCP bandwidth, and it is really useful to test how stuff works on slow connections.
Is there something similar to iprelay, which will allow me to ...
2
votes
3answers
77 views
Processes in uninterruptable sleep killing server
I have a opensuse 11 64 bit server with some issues I'm not sure how to solve. I'm getting hundreds of these in the porocess list:
4 0 3105 1 20 0 55420 3488 646312 Sl ? 0:02 ...
-2
votes
4answers
108 views
what are all the common factors affecting VM performance? [closed]
Recently we faced a performance problem in our ESXi 4.1 hosted in Dell R710 server.
I verified RAM and it was 48 GB. I checked the CPU it was quadcore. Finally i came to know that the server had only ...
0
votes
5answers
235 views
What are the more reliable SSDs to use in an enterprise environment?
We all know SSDs are fast... but aren't all that great when it comes to any computer that writes to disk many times in any given minute.
Are there any SSDs that are suited for an enterprise ...
0
votes
3answers
57 views
Resource monitor and how to spot if you have disk I/O problems?
I have an application server which runs pervasive SQL and app using it.
Last weeks the users are complaining about poor performace of the app and I suspect disk I/O problems because CPU and RAM ...
3
votes
3answers
271 views
Large disk queue length
A few days ago disk on my server started to have large queue length:
I've changed controller battary recently, HP configuration utility was saying the battery is bad, but after changing the battery ...
1
vote
1answer
197 views
Poor hard drive performance
I have nearly two identical servers, the only difference between the
two is the version of Linux and the Hard Drive. Server 1 had (what I
think) is a better drive, therefore the performance should be ...
0
votes
2answers
168 views
Disk warning 51 on Windows 2008 x64 Standard R1
I keep getting a disk warning 51 message in the system log every few months. It eventually causes the server to crash (killing all my network services), forcing me to do a hard reboot.
Full error ...
0
votes
4answers
152 views
SQL Server: One 12-drive RAID-10 array or 2 arrays of 8-drives and 4-drives
Setting up a box for SQL Server 2008, which would give the best performance (heavy OLTP)? The more drives in a RAID-10 array the better performance, but will losing 4 drives to dedicate them to the ...
1
vote
1answer
84 views
Server freeze (Disk I/O possibly)
I have a Windows Server 2008 machine that is resyncing disks after a powerloss. The issue is that the system becomes unresponsive after about 10 minutes. We've checked with resource monitor and found ...
1
vote
0answers
44 views
Benchmarking a file server
I'm working on building a new file server... a simple Windows Server box with a few terabytes of disk space to share on the LAN. Pain for current hard drive prices aside :( -- I would like to get ...
3
votes
1answer
166 views
Poor NFS performance when sequentially reading large files
I have an NFS3 server with multiple clients. Each client is sequentially reading a different large file, and performance is very poor.
Here is what I am observing in iostat on the server for the disk ...
0
votes
0answers
31 views
How do I get AvgDiskSecPerWrite to return the same value as the object in perfmon instead of 0?
I am trying to query WMI to get the value for AvgDiskSecPerWrite from Win32_PerfFormattedData_PerfDisk_PhysicalDisk using WQL with the following query
SELECT AvgDiskSecPerWrite FROM ...
0
votes
0answers
27 views
compress to another disk, then move back slower than operating on single disk
Could you help me understand performance differences, I've experienced compressing some data?
The story is that I compress various files (20kB-600MB) in 2e20 chunks from one LUN to another.
Then I ...
1
vote
0answers
468 views
High disk I/O activity in CentOS server
I have about 16 websites in a CentOS dedicated, and I am having some problems on high traffic hours, it seems to be a high disk I/O activity causing a general slowdown.
I've installed atop and this ...
1
vote
1answer
55 views
How is the average seek of disk estimated given a function to move head to n track
How is the average seek time of disk calculated if a function f(x) is given as an estimate of time to move head of disk to n tracks?
0
votes
2answers
216 views
How to remove swap partitions from RAID 1 Array on Ubuntu?
Can anyone point in the right direction on how to remove SWAP out of a RAID1 configuration on Ubuntu 10.04 server? According to the Ubuntu Advanced installation guide, here, it said to add swap to the ...
2
votes
0answers
170 views
Apache's htcacheclean doesn't scale: How to tame a huge Apache disk_cache?
We have an Apache setup with a huge disk_cache (>500.000 entries, >50 GB disk space used).
The cache grows by 16 GB every day.
My problem is that the cache seems to be growing nearly as fast as it's ...
1
vote
1answer
482 views
fio config to measure IOPS against provider SLA
So a provider has given us 500 IOPS/TB as their SLA standards for disk performance in a VMWare & RAID5-SAN environment. This is apparently measured with:
16kB average transfer block size
3:1 ...
5
votes
1answer
148 views
At what point is EBS usage the bottleneck?
I've got a site hosted on Amazon using a EC2 instance backed by an EBS volume. On the weekends, traffic spikes and I make the instance larger which helps quite a bit -- I'm no longer seeing CPU usage ...
-1
votes
2answers
84 views
How to perform Server Performance Audit [closed]
Here is the situation. I am the CIO in my work place. The guy on the management team that get to take decision regarding Techy things. I dont do actual development, but we have an IT service provider ...
0
votes
2answers
225 views
md-RAID5 - How fast should it be or where is the bottleneck?
I set up a new server with a LUKS encrypted RAID5. On the former server, the bottleneck was definitely the CPU, as it was a 7y old single core and the load went up to 100%.
Now it is different. I ...
9
votes
2answers
374 views
How does Linux handle concurrent disk IO?
When a Linux server is serving many concurrent requests to read many different files, does it:
Seek to File_1, read the entire file, then seek to File_2, read the entire file, then seek to File_3, ...
7
votes
1answer
235 views
RAID with 4 drives offers very minimal speed improvement
Setup
1.5TB x 8 on a SANS Digital enclosure configured into two sets of 4 drives and connected to a Windows Server 2003 computer over eSATA. They are all identical Seagate Barracuda ST31500341AS ...
0
votes
1answer
63 views
MS Server 2008 NLB: Writing on Harddisk
I'm in a confusing situation right now: I have 2 MS Server 2008, hosting a WCF-Webservice which is basically reading data from an SQL-Server and forwarding it to the client.
We use NLB to loadbalance ...
0
votes
1answer
156 views
Appropriate Linux (ubuntu 10.04) FS type for rapid FS management many small files and directories [closed]
Possible Duplicate:
Linux's best filesystem to work with 10000's of files without overloading the system I/O
I have an 240gb image store of approximately 1.5 million entries. About ...
4
votes
4answers
807 views
PERC 6/i RAID on Dell R710: Slow disk… RAID10 on single controller?
There are multiple questions here - but it starts with this: we've a Dell PowerEdge R710 with a PERC 6/i RAID controller (or controllers) in a RAID10 configuration.
The system is running Ubuntu ...
1
vote
1answer
110 views
RAID config. for a Heavily Used File Server
I'm building a new file server to replace an existing server. The current workload is about 50 connections that are heavily reading and writing files all day long. It is about 50/50 read to write. ...
1
vote
1answer
267 views
iotop for Linux kernel 2.6.18
So it has to come to my attention that iotop isn't availalbe for 2.6.18 since it's less than 2.6.20 and requires Python 2.6+. I've done some research and came across this article:
...
