Boot from SAN

Anyone out there booting unix hosts - preferably Solaris - from a SAN? Have
you integrated JumpStart or similar utility with it?

"Michael Kramer" wrote in message ...
Anyone out there booting unix hosts - preferably Solaris - from a SAN? Have
you integrated JumpStart or similar utility with it?

I heard from one of the Windows guys that booting from SAN on windows
is risky, as pagefile latency is very high. Not sure on Solaris.
Does that hold true on Solaris also ?

s_t_o_r_a_g_e wrote:
"Michael Kramer" wrote in message
...
Anyone out there booting unix hosts - preferably Solaris - from a
SAN? Have you integrated JumpStart or similar utility with it?

I heard from one of the Windows guys that booting from SAN on windows
is risky, as pagefile latency is very high. Not sure on Solaris.
Does that hold true on Solaris also ?

If you have a dodgy SAN with lots of dropped packets or an overloaded array
that can't handle the workload, then this would be a concern. In practice
though, there is no significant difference between having a direct attached
FC array and a SAN attached FC array as the boot device for either Solaris
or Windows, both will function quite happily in this mode (and I'm speaking
from experience.)


--
Nik Simpson

I would add that in todays hardware if you're paging to swap then you
probably have a misbahaving application. I don't think I've had a
server page to swap (except an NBU box) in almost 2 years.

~F

On Wed, 7 Jan 2004 08:09:45 -0500, "Nik Simpson"
wrote:

s_t_o_r_a_g_e wrote:
"Michael Kramer" wrote in message
...
Anyone out there booting unix hosts - preferably Solaris - from a
SAN? Have you integrated JumpStart or similar utility with it?

I heard from one of the Windows guys that booting from SAN on windows
is risky, as pagefile latency is very high. Not sure on Solaris.
Does that hold true on Solaris also ?

If you have a dodgy SAN with lots of dropped packets or an overloaded array
that can't handle the workload, then this would be a concern. In practice
though, there is no significant difference between having a direct attached
FC array and a SAN attached FC array as the boot device for either Solaris
or Windows, both will function quite happily in this mode (and I'm speaking
from experience.)

In article , Faeandar wrote:
I would add that in todays hardware if you're paging to swap then you
probably have a misbahaving application. I don't think I've had a
server page to swap (except an NBU box) in almost 2 years.

So, what do you have swap space for?

Regards,

Florian

I don't.

Of course that is the short answer....

On 98% of machines I do not have a swap partition other than what I
reserve for /tmp. That other 2% consists of critical app servers
that, if the app goes beserk on memory, still need to be up until a
scheduled maintenance can occur.

~F


On Thu, 8 Jan 2004 00:43:41 +0100, Florian Laws
wrote:

In article , Faeandar wrote:
I would add that in todays hardware if you're paging to swap then you
probably have a misbahaving application. I don't think I've had a
server page to swap (except an NBU box) in almost 2 years.

So, what do you have swap space for?

Regards,

Florian

Every OS pages I think you should checkout any moden day operating systems
book.

- RB

"Faeandar" wrote in message
...
I don't.

Of course that is the short answer....

On 98% of machines I do not have a swap partition other than what I
reserve for /tmp. That other 2% consists of critical app servers
that, if the app goes beserk on memory, still need to be up until a
scheduled maintenance can occur.

~F


On Thu, 8 Jan 2004 00:43:41 +0100, Florian Laws
wrote:

In article , Faeandar wrote:
I would add that in todays hardware if you're paging to swap then you
probably have a misbahaving application. I don't think I've had a
server page to swap (except an NBU box) in almost 2 years.

So, what do you have swap space for?

Regards,

Florian

Michael Kramer wrote:
: Anyone out there booting unix hosts - preferably Solaris - from a SAN? Have
: you integrated JumpStart or similar utility with it?

I haven't setup jumpstart to install to a SAN volume. I do not think
it would be possible to have a fully automated install with QLogic HBAs.
Maybe with Sun ones. The QLogic cards require too much interaction
with the FCODE...

But I have installed the OS to a local disk and then moved it to a
SAN disk. And I can tell you that my boot time dropped going from an
IDE disk to a T3. I even tossed a few more switches in between the
host and storage with redundant paths and did some error injection.
It worked really slick.

Lyle

Every OS *can* page, doesn't mean they will. If you do not give it a
place to dump memory it will stay in memory. As long as my host has
enough memory to run all the things it needs to there is no need to
page memory out to disk.

~F

On Thu, 08 Jan 2004 13:00:25 GMT, "Rodrick Brown"
wrote:

Every OS pages I think you should checkout any moden day operating systems
book.

- RB

"Faeandar" wrote in message
.. .
I don't.

Of course that is the short answer....

On 98% of machines I do not have a swap partition other than what I
reserve for /tmp. That other 2% consists of critical app servers
that, if the app goes beserk on memory, still need to be up until a
scheduled maintenance can occur.

~F


On Thu, 8 Jan 2004 00:43:41 +0100, Florian Laws
wrote:

In article , Faeandar wrote:
I would add that in todays hardware if you're paging to swap then you
probably have a misbahaving application. I don't think I've had a
server page to swap (except an NBU box) in almost 2 years.

So, what do you have swap space for?

Regards,

Florian

"Faeandar" wrote:
Every OS *can* page, doesn't mean they will. If you do not give it a
place to dump memory it will stay in memory. As long as my host has
enough memory to run all the things it needs to there is no need to
page memory out to disk.

It is OK if you have too much money. But most people will find that a
page/swap file will give the system the ability to use memory more
efficiently. There is less incentive if the system can discard parts of a
program which is not needed. I believe OpenVMS does not page programs; it
reloads from the file.


greetings,