10
votes
3answers
721 views

Why is my RAID1 read access slower than write access?

I have done some simple performance tests and it seems that reading from my RAID1 is slower than writing: root@dss0:~# for i in 1 2 3; do dd if=/dev/zero of=/dev/sda bs=1048576 count=131072; done ...
12
votes
7answers
547 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 ...
5
votes
2answers
362 views

Why would Linux VM in vSphere ESXi 5.5 show dramatically increased disk i/o latency?

I'm stumped and I hope someone else will recognize the symptoms of this problem. Hardware: new Dell T110 II, dual-core Pentium G850 2.9 GHz, onboard SATA controller, one new 500 GB 7200 RPM cabled ...
4
votes
1answer
138 views

Mail Server Storage Backend: Filesystem VS Database

I am trying to compare mail server software to decide which to use at the ISP where I work. I'm confused mainly about which storage backend is better for such use (again, at an ISP, i.e expected large ...
3
votes
1answer
89 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. ...
0
votes
3answers
112 views

Linux: Get information/stats about storage network

I want to know as much info as possible about the SAN a linux server is connected to. What commands will give me the most comprehensive view? Simply knowing the WWN of LUNS doesn't do much for me. ...
1
vote
2answers
315 views

HP Smart Array P822 w. Dual D2700 - cabling for best performance

Reading the D2600/D2700 User guide, there's a section called "Cabling examples", but none of the examples match what we intend to do. I just want to make sure that it makes sense, before we do it. ...
1
vote
3answers
316 views

How many IOPS do I need? My workload bottleneck is storage

How can I know how many IOPS I need my storage to deliver for my overloaded Linux server? I have a server and I know it has storage as its bottleneck. I would like the bottleneck not to be storage, ...
1
vote
1answer
184 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++ ...
0
votes
0answers
28 views

How to benchmark a whole storage infrastructure

I'm a 100% sure that I'm not the first one to consider benchmarking a whole infrastructure, but yet I haven't found any relevant information on how to face this challenge. As I guess we all know what ...
2
votes
0answers
67 views

Infiniband link is at 4X SDR with DDR HCAs; has anyone seen this before?

I've recently upgraded my Infiniband HCAs from SDR to DDR, however upon upgrading, it has not improved the link speed at all. Receiving the following output from 'iblinkinfo': CA: ip-san-1-au3a ...
1
vote
0answers
250 views

windows2012 failover cluster + storage. Considerations

We plan to build a failover storage with Windows2012r2. There will be 2 or 3 physical machines with 2 virtual machines on each server. One virtual machine building a failover, second one being storage ...
3
votes
1answer
114 views

Poor NFS Performance Using Multiple Disks

I have a server system running Ubuntu 12.10 with 12 disks attached. I am sharing all of these disks on my 10 gigabit network using NFSv4. However, I am getting generally poor performance over NFS ...
2
votes
1answer
78 views

Creating “Odd” Size Disks in VmWare/Linux

I believe I suffer from "everything must be in powers of 2" syndrome. When asked to create a 30G disk in VmWare for a VM I want to create a 32G disk. If someone needs 256G of storage using LVM I ...
8
votes
1answer
2k views

Is calculating IOPS for ZFS RAIDZ different then calculating IOPS for RAID5 & RAID6?

When calculating IOPS for traditional RAID arrays, one could use the following formula (Borrowed from Getting The Hang Of IOPS v1.3 on Symantec Connect): Ieffective = (n * Isingle) / (READ% + (F * ...
-1
votes
2answers
363 views

What is the best way for store images of website? [closed]

We are using cassandra database for store website information, but we are not sure how to save images. We can store them in cassandra, but we can also allocate a server for storing images. ...
0
votes
1answer
502 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 ...
3
votes
4answers
282 views

rm intermittently causes disk to lock up

I have encountered this extremely strange problem on two servers now, both running CentOS5, both of them ext4. One is a SSD, the other is a regular hard drive, both SATA without RAID. The issue is ...
3
votes
2answers
339 views

Linux - Storage IOPS

I have number of MySQL databases, I have used tools such as dstat, vmstat I'm just unable to determine when do I need to add more drives to increase performance. the number of databases are ...
1
vote
1answer
86 views

RAID: is it enough to have n+1 disks in a RAID6 array to match performance of a n disks RAID5 array? [closed]

As far as I know, RAID-6 has an even worse penalty on writes than its cousin RAID-5. But we also know that we can get more performance out of a typical RAID array by having more spindles in it. But ...
1
vote
2answers
2k views

Determining cause of high NFS/IO utilization without iotop

I have a server that is doing an NFSv4 export for user's home directories. There are roughly 25 users (mostly developers/analysts) and about 40 servers mounting the home directory export. ...
2
votes
1answer
239 views

How to get started troubleshooting Linux mdadm raid10 write performance?

Using Linux mdadm, I've setup a six disk raid10,f2 array. I'm using 7200RPM SATA drives. The biggest load I am worried about is recording four streams of live video (worst case of 20Mbits each, final ...
2
votes
1answer
106 views

Performance issue in using Amazon S3 for run-time updates

I have a web application hosted in Amazon EC2 as well as in Rackspace. Users can upload files through this application and also modify them. Those files are stored in local storage in each of these ...
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) = ...
3
votes
2answers
2k views

Sheepdog versus iSCSI for KVM

What is recommended storage solution as VM count grows? We currently have 5 VM servers (8 core, 32GB) and one storage server. Currently we have ~80 virtual machines running and the storage server's ...
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 ...
3
votes
4answers
1k views

Is there a performance advantage to isolating database logs and data on different volumes (same RAID array) across a SAN?

On my old server, I separated them on to different RAID arrays to improve performance. Using a SAN is new to me, so I'm not sure of the optimal configuration. SAN: 48 drives. 10K 600GB SAS. RAID 50. ...
2
votes
3answers
9k views

Measure Linux IOPS for a running system

How do I measure IOPS of a running Linux server? I know that the theoretical IOPS of a SATA drive is around 90 and enterprise 10k SAS/FC disk is 180. I want to know how much my running system is using ...
3
votes
2answers
178 views

Flushing disk cache for performance benchmarks?

I'm doing some performance benchmark on some heavy SQL script running on postgres 8.4 on a ubuntu box (natty). I'm experiencing some pretty un-stable performance, even though I'm supposed to be the ...
2
votes
4answers
260 views

Why should I choose an Enterprise Storage Vendor?

I have been basically psyched out by some of the sales consultants from enterprise vendors such as EMC and NetApp. We have a new requirement to store around 30 TB of unstructured data, and around ...
0
votes
3answers
655 views

RedisToGo - remote Redis server. When to use one?

I like the concept of relying on third-party service hosting my data but what's the point of using super-fast NoSQL storage via remote hosting? It maybe in different datacenter or even country! And ...
2
votes
2answers
104 views

Setting up Multi-server Infrastrure? Advise the best options

We are setting up a number of Virtual Machines (around 250) for a customer who is basically using an application written in LAMP + Java with a bit of customizations in each of these 250 instances. ...
-1
votes
2answers
122 views

Hard Disk Speed for Virt Laptop [closed]

If I want to run a few dev VMs on a laptop, how fast do my drives realistically need to be? I do not expect lightning fast performance, but the last time I tried this on a Lenovo Thinkpad T400, ...
2
votes
1answer
109 views

Is it Good to place Windows Server paging files on seperate fast storage?

How much of an impact does the performance of the storage system hosting the paging files of windows machines (I guess both physical or virtual instances like VMWare / KVM / Xen / Whatever)?
0
votes
1answer
148 views

2 JBOD enclosures 1 RAID controller vs 2 RAID enclosures

In term of scalability of performance and price, what would be better for a small business with around 20 users. I am targeting around 45TB of storage via SAS. Here are my options: Buy 2 JBOD ...
4
votes
3answers
3k views

Improving RAID performance

I just installed an LSI 9260-i8, using two virtual drives, the first composed of 4 SSDs, the second of 4 HDDs. Obviously the idea is to get better performance while maintaining some security and ...
1
vote
4answers
3k views

HP smart array P812i and storage works enclosure D2700 BAD PERFORMANCE!

I have HP DL360 G6 with Smart Array P812i and Storage Works D2700 enclosure. Enclosure has 25x148GB 15K SAS 6G drives in RAID10 mode. P812i has 512mb cache (50% read/50% write) Crystal Disk mark ...
2
votes
1answer
562 views

Recommended technology for layered disk cache in linux

I originally asked this on superuser but it occurs to me it's more more of a server topic. I've just bought a 6-core Phenom with 16G of RAM. I use it primarily for compiling and video encoding (and ...
0
votes
2answers
7k views

what is the throughput of 15K RPM SAS drive? [closed]

bandwidth for a single 15K RPM disk ? 10MBps or 100MBps?
1
vote
2answers
1k views

anyone using coraid storage: ATA over ethernet?

can these enclosures be populated with SATA or SAS drives purchased elsewhere? recently Dell has made custom size slots on their PE T710 servers on which you could only place drives purchased from ...
0
votes
1answer
744 views

How to design high performance CIFS/SMB

Would it make sense to virtualize windows using Xen or VMware ESX and expose storage on a JBOD as NFS, instead of exposing storage as CIFS/SMB for better I/O throughput? Is it true that the below can ...
4
votes
4answers
7k views

Howto check disk I/O utilisation per process

Im having a problem with a stalling Linux system and I have found sysstat/sar to report huge peaks in disk I/O utilization, average service time as well as average wait time at the time of the system ...
0
votes
4answers
260 views

RAID vs Separate HDD's

What would be more efficient? Let say we have 2 hdd's. Consider this scenario: There are 2 simulations requests. In the RAID-0 setup the speed of the response will be boosted by the array. In ...
0
votes
2answers
185 views

Database Performance Across 3 NetApp FAS2050

I recently inherited a SQL Server 2005 box that has LUNs mounted on it from three different NetApp FAS2050 filers. The reason there are three is because the first two filers are out of space and our ...
4
votes
2answers
179 views

Storage sizing for virtual machines

I am currently doing research to determine the consolidation ratio my company could expect should we start using a virtualization platform. I find myself continually running into a dead end when ...
1
vote
1answer
321 views

Linux Cache Clear for Storage Performance Testing

Is there any way to make linux remove from memory all cached disk data? Our goal is to time some performance tests on various storage configurations and have each one start with a clean slate ...
0
votes
1answer
59 views

Relative seek times for various types of storage media

Does anyone know the approximate time required to retrieve and modify a kilobyte of data for various types of storage media in a typical modern server? Specifically: RAM Hard disk SSD This would ...
2
votes
1answer
682 views

Is basing storage requirements based on IOPS sufficient?

The current system in question is running SBS 2003, and is going to be migrated on new hardware to SBS 2008. Currently I'm seeing on average 200-300 disk transfers per second total across all the ...
1
vote
4answers
247 views

file share system architecture asking for advice

I am using Windows platform to setup a web based file share system. In more details, individual users could upload and share documents from web interface (content may be big document, like video ...
0
votes
2answers
94 views

HPC Data-Access & Storage Design

I'm currently working with a cluster-configured application that stores all data locally for each child node. We're having issues scaling up properly and are looking into traditional SAN and ...