Solved

vsphere disk latencies server down

Posted on 2011-09-26
10
1,048 Views
Last Modified: 2012-05-12
every few weeks our vsphere 5 server goes on the run.
all applications time out, vsphere client shows that disk latencies on all services go sky-high (see screenshot).
my only solution is a reboot of the physical server and restart each virtual server.
unix servers usually need a fsck in single user mode to get rid of errors.
what could be cause of these extreme latencies ?

we use vsphere 5 on a raid-5 of 6 x 500gb local sata disks.

vsphere-latencies.jpg
0
Comment
Question by:Lieven Embrechts
  • 5
  • 4
10 Comments
 
LVL 118
ID: 36600973
Are the 6 SATA disks 7,200 RPM?

6 SATA disks, RAID 5 - is going to have performance issues.

How much ram in the HOST server?

How much ram is being used by guests?
0
 
LVL 9

Author Comment

by:Lieven Embrechts
ID: 36601001
yes, 2.5 inch 7200rpm.

enough ram in server (12 of 24gb used), guests look ok for ram usage when server runs normal.

i'm not an expert on vsphere but it feels like the IO queue is overloaded somehow, and when that happens the complete vsphere environment goes on the run ...
0
 
LVL 118
ID: 36601043
It's the 7,200rpm SATA disks.

What's the server and RAID controller?
0
 
LVL 9

Author Comment

by:Lieven Embrechts
ID: 36601551
cisco ucs c210 m2 server
lsi 6g megaraid 9261-8i - 512wc card
0
 
LVL 118
ID: 36601603
Have you got the RAID cache set to 75% Write 25% Read?

On a production machine I would not use 7,200rpm disks, the IOPs would be very poor, and worse in a RAID5 configuration.
0
Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

 
LVL 9

Author Comment

by:Lieven Embrechts
ID: 36601665
>>Have you got the RAID cache set to 75% Write 25% Read?

if it's not default, why would i do that, where would i do that ?

>>On a production machine I would not use 7,200rpm disks, the IOPs would be very poor, and worse in a RAID5 configuration.

consultant used raid 6 i believe, he told me all IO would be distributed over the disks so better performance with raid 5 or 6.
what would be your suggestion for disks and raid-config ?

is the graphic you see (see screenshot) something seen before ? reason ?
0
 
LVL 118
ID: 36601684
SATA disks are very slow, poor performance, should only be used for Labs, Research, or Archives/Backup.

Your issues, is your poor SATA disks.

RAID 10 is faster for read and writes.

RAID Cache Configuration can be changed in the RAID BIOS.
0
 
LVL 42

Expert Comment

by:paulsolov
ID: 36646016
I would agree with hanccocka, SATA drive can pose problems.  Take a look at what is happening on the guest side such as a SQL server doing maintenance work on a database.  I would also ensure that the 75% write, by default I think the UCM servers are 50/50 which can slow down the write performance and as you can see it's thw write latency you're having an issue with.  SAS drives would be preferred.
0
 
LVL 118

Accepted Solution

by:
Andrew Hancock (VMware vExpert / EE MVE) earned 500 total points
ID: 36647581
0
 
LVL 9

Author Comment

by:Lieven Embrechts
ID: 36895834
had a look at the cache settins several were referring to:
apparently the lsi controller is by default full write cache, there is no read cache.
as for the sata disks, i don't see a problem with light apps & light load.

write latencies go up all of a sudden every 2 days at random time,
i need a method to find what is causing it.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Last article we focus in how to VMware: How to create and use VMs TAGs – Part 1 so before follow this article and perform the next tasks, you should read the first article how to create the TAG before using them in Veeam Backup Jobs.
In this article, I will show you HOW TO: Create your first Windows Virtual Machine on a VMware vSphere Hypervisor 6.5 (ESXi 6.5) Host Server, the Windows OS we will install is Windows Server 2016.
Teach the user how to install log collectors and how to configure ESXi 5.5 for remote logging Open console session and mount vCenter Server installer: Install vSphere Core Dump Collector: Install vSphere Syslog Collector: Open vSphere Client: Config…
Advanced tutorial on how to run the esxtop command to capture a batch file in csv format in order to export the file and use it for performance analysis. He demonstrates how to download the file using a vSphere web client (or vSphere client) and exp…

867 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

19 Experts available now in Live!

Get 1:1 Help Now