There are two things i noticed which might affect performance negatively:
Quote:
Originally Posted by c3rb3rus
You can increase this to help especially larger transfers. Use the -R switch of lsattr to see legal values you can use.
These two:
Quote:
Originally Posted by c3rb3rus
are also not optimal. Basically the multipath drivers (can) use multiple pathes (FC connections from the LUN to the system) at once. These multiple pathes can be used for two purposes: the first is redundancy, so that if one connection fails it uses another. Connection failure - temporarily - happens rather frequently for reasons i don't fully understand in FC-connections. The other purpose multiple pathes can be used to is performance: using several pathes in parallel speeds things up. This is basically controlled by using the "algorithm" property. I have no test system at hand to tell you the value you need to use but there are only two of them and you need the other one - again, use the lsattr -R switch to list all legal values for the property.
The reserve_policy should be "no_reserve" but this matters mostly in clusters where disks are accessed from several systems at once.
can someone tell me a good site to go to in order to learn this. please do not recommen nay books because i dont have interest in that. if you know of any good sites with good straight forward explanation on how to split loads on machines that has excessive loading, please let me know
Also,... (1 Reply)
Hi all,
long time ago I posted something, but now, it is needed again :(
Currently, I am handling with a big NFS Server for more than 200 clients, this sever has to work with 256 NFSDs. Because of this huge amount of NFSDs, there are thousands of small write accesses down to the disk and... (3 Replies)
Hi to all,
I'm interested in finding an introduction about Performance Tuning under Unix (or Linux); can somebody please point me in the right direction?
Best regards (1 Reply)
Sorry,
This is out of scope of this group.But I require the clarification pretty urgently.
My Oracle database is parallely enabled.
Still,in a particular table queries do not work "parallely" always.
How is this? (9 Replies)
Hi All,
In last one week, i have posted many questions in this portal. At last i am succeeded to make my 1st unix script.
following are 2 points where my script is taking tooooo long.
1. Print the total number of records excluding header & footer. I have found that awk 'END{print NR -... (2 Replies)
Hi all,
From Googling, I found that the basics used for troubleshooting UNIX/AIX performance issues are commands like vmstat, iostat and sar. I believe these are generic commands regardless of what UNIX flavour is in used, only difference being is the format of the output.
In a real case... (2 Replies)
Please take a look at this system and give your analysis / advice. Can it be tuned to get a better performance?
We are not getting more hardware ressources at the moment.
We have to live with what we have. Application running on the system is SAS. OS is AIX 6.1
Let me know if you need output of... (7 Replies)
Dear all,
I have a Local zone , where users feel that performance is not good.
Is it wise to collect the inputs from the local zone rather than taking from the global zone.
And also Can I tune from Global zone , so that it will reflect in local zone.
Rgds
rj (2 Replies)
Overview:
Introduction
What Does Success Mean?
What Does Performance Mean?
Every Picture is Worth a Thousand Words
Work Like a Physicist
Work Like You Walk - One Step at a Time
Learn to Know Your System
Choose Your Weapons!
Tools of the Trade 1 - vmstat
A Little Theory Along the Way -... (1 Reply)
Discussion started by: bakunin
1 Replies
LEARN ABOUT HPUX
nfs4_nra
nfs4_nra(5) File Formats Manual nfs4_nra(5)NAME
nfs4_nra - control the number of read-ahead operations queued by the NFS version 4 client when sequentially accessing a file
VALUES
Failsafe
Default
Allowed values
Recommended values
A warning will be issued at runtime if the tunable is set to a value greater than 16 since this is beyond the tested limit. This is not a
serious warning but just an information message for the administrator.
DESCRIPTION
controls the number of read-ahead operations that are queued by the NFS version 4 client when sequential access to a file is discovered.
These read-ahead operations increase concurrency and read throughput. Each read-ahead request is generally for 32768 bytes of file data.
Who Is Expected to Change This Tunable?
The distributed file system administrator should examine this value depending on network bandwidth and memory pressure on the client.
Restrictions on Changing
The tunable is dynamic; tuning will take effect immediately on the running system.
When Should the Value of This Tunable Be Raised?
If the network is very high bandwidth and the client and server have sufficient resources, increase this value to more effectively utilize
the available network bandwidth, the client resources, and the server resources.
What Are the Side Effects of Raising the Value?
Tuning incorrectly based on network bandwidth can cause performance problems.
When Should the Value of This Tunable Be Lowered?
In a very low bandwidth network, decrease this value so the NFS client does not overload the network.
What Are the Side Effects of Lowering the Value?
Tuning incorrectly based on network bandwidth can cause performance problems.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its meaning changed in future releases of
HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun-
able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was
factory installed on your system, see at
AUTHOR
was developed by Sun Microsystems, Inc.
SEE ALSO kctune(1M), sam(1M), gettune(2), settune(2), nfs2_nra(5), nfs3_nra(5), values(5).
Tunable Kernel Parameters nfs4_nra(5)