Hi,

Is there anyway that I can collect real IOPS on my server & storage?
I'm running sol 8, 9, & 10 and sun storage T3B.  One suggests to run
iostat -xcnCXTdz 5 but I don't see that I gather enough info.  Is
there a way to collect IOPS on my server & storage?  Any suggestion
are greatly appreciated.

Thx,
-Chris

On Mar 8, 11:08 pm, "lazyboy...@yahoo.com" <lazyboy...@yahoo.com>
wrote:
> Hi,
>
> Is there anyway that I can collect real IOPS on my server & storage?
> I'm running sol 8, 9, & 10 and sun storage T3B.  One suggests to run
> iostat -xcnCXTdz 5 but I don't see that I gather enough info.

What information are you after that isn't there?  the r/s and w/s
figures are the number of read or write ops/second on the disks, the
other fields have interesting meanings as well, described in the
manuals (you really need a book which talks about I/O properly to
understand some of them, as you need to know a little bit about
queuing theory to know when things are bad (for instance I think you
never want devices to be 100% busy (the %b field) and there is some
degreee of busyness below that where the performance maximum is).

--tim

We are planning to upgrade our production servers & storage which were
bought 7 yrs ago.  So, in order to have a successful proposal, I have
to understand exactly (or very close) our current IOPS on the
storage.  When I read the output of iostat -xcnCXTdz 5, I don't
understand what is a distinct difference between r/s vs. kr/s and also
w/s vs. kw/s, and yes, I did read the iostat man page.  When you are
calculating IOPS, are you looking at r/s or kr/s field?  Now, in term
of the total IOPS, are we looking a disk as lun or how does it go?
You mention about a book which talks about I/O property.., do you
happen to know the name or url that I read it online?  I really
appreciated your inputs.

Thx,
-Chris

On 2007-03-09 16:59:43 +0000, "lazyboy_2k@yahoo.com" 
<lazyboy_2k@yahoo.com> said:

> When I read the output of iostat -xcnCXTdz 5, I don't
> understand what is a distinct difference between r/s vs. kr/s and also
> w/s vs. kw/s, and yes, I did read the iostat man page.

r/s and w/s are the number of read and write operations for the thing 
(see below for meaning of "thing") you're looking at. kr/s and kw/s are 
the number of kbytes read or written per second.  dividing one by the 
other gives you the average transfer size.

>  When you are
> calculating IOPS, are you looking at r/s or kr/s field?

for IOPS r/s and w/s.  However depending on the load on the machine the 
bandwidth may also be interesting (though IOPS is more commonly an 
issue for, say, transactional database loads).

> Now, in term
> of the total IOPS, are we looking a disk as lun or how does it go?

This depends enormously on what I think of as the geometry of the 
storage (what the "thing" is above).  Typically a given disk will have 
limits on what it can do, both in terms of IOPS and bandwidth, but if 
you are using any kind of RAID this may be obscured as spindles are 
combined together in various ways which affect the performance.  If 
you're using purely software RAID (SVM or ZFS) then you have the luxury 
of being able to see down to the individual spindles very easily.  If 
you're using systems with hardware RAID then this is harder (though the 
array itself may well support inspection tools in that case).  You also 
have to be aware of multiple Solaris devices which are really the same 
device - such as slices or soft partitions, but also multiple LUNs made 
available from the same group of disks from some hardware device. 
Finally there may be limits imposed by the controller and the 
interconnect.

> You mention about a book which talks about I/O property.., do you
> happen to know the name or url that I read it online?  I really
> appreciated your inputs.

The only reference I can think of off the top of my head is Hennesey 
and Patterson, but that doesn't really talk about storage in any 
detail.  There must be better books.

If this is a major upgrade (rather: if it's an expensive upgrade) I'd 
consider getting some specialist consultancy (but not from anyone who 
wants to sell you storage, because you know what they will say).

--tim

On Fri, 09 Mar 2007 19:06:58 +0000, Tim Bradshaw wrote:
> The only reference I can think of off the top of my head is Hennesey and
> Patterson, but that doesn't really talk about storage in any detail. 
> There must be better books.

Configuration and Capacity Planning for Solaris Servers
by Brian Wong

- Jeremy