Re: OT: Sparc not dead yet

Main, Kerry wrote:
Would you be willing to pay extra for this hot swap capability vs using
VMS servers on std HW (cheaper)

If your saying the cost of the hot-swap 'PCI' card capability in
hardware, would make hardware more expensive, then maybe you need to
review the facts, that capability is already in VMS supported hardware.
Marvel's specifically.

From the HP website..

http://h18002.www1.hp.com/alphaserver/download/html/dhb_ev7_alphaserver_delivers_061703.html

"The I/O drawers offer hot-plug capability so the I/O adapter cards can
be repaired/replaced without taking the system down."

It's also been confirmed to me from other people in HP, or if you like
just open up an IO Drawer on a Marvel and look for the thumb-screw
plates that hold in the 'PCI' cards. The ones that have purple/red
thumb-screw plates, were designed to be hot-swappable in hardware.

And with PCI-E coming along, I suspect a lot of future Integrity boxes
will also support it.

If you have this capability, local HW hot-swapping becomes
much less of
an issue. Especially if FC/NIC adapters are implemented with teaming
design. If one adapter fails, simply schedule a time for
the system to
be taken down and have it replaced. Since you do not need
to tell end
users about this server going, they will not care.

As per my last mail, thats what I already do. With the increased costs
of the extra cards, to impliment FailSafe on top of LAN failover (so as
I don't get a performance hit). What I would like as an option however
would be to hot-swap the cards and then just have FailSafe on some
boxes (in the case of NICs).

With that project I worked on, using TCPware, we were able to
telnet to a server, start a monitor system type command to generate
activity, pull the associated NIC cable and the session continued
running after only about a 2-3 second pause. No errors and no loss of
data. With TCPware, we could see that the NIC failed over properly. This
also supported fail-back as well i.e. when we re-connected the NIC cable
after a 2-3 second pause, the connection automatically failed back to
the original port.

As per TCP/IP Services FailSAFE IP, and VMS' LAN Failover.


As I'm sure your aware FailSafe IP also gives you added performance
benfits for your outgoing traffic, if there in the same subnet. Losing
a card drops your performance. And yes the obvious workaround is to
deploy FailSafe on top of LAN Failover, with the added cost.


As you indicated, the loss is in transmit only i.e. perhaps if you had a
big FTP background load, there might be some loss, but remember that the
overall load is also split across the other servers in the cluster as
well. I doubt end users would notice the impact of one NIC failing on
one server in the cluster when its mate takes over.

Users don't notice, nor do batch jobs, as I tend to impliment FailSAFE
on top of LAN Failover. If I just had FailSAFE, then I would get the
performance hit. And sure the users wouldn't notice, but large data
transfers being generated by batch jobs in progress would notice.

FC cards same issue, you lose performance, possible path
changes across
the cluster et al.


Heck, the 2Gb cards I have used for the last 2 years or so have not been
pushed at all - even with high IO loads.

If that were true in all cases, it makes you wonder why VMS Engineering
are qualifing 4GB HBAs with Integrity boxes?

And indeed, support in VMS is already latent in F8.3.

$ write sys$output f$gets("version")
F8.3
$ sea sys$system:sys$config.dat "Qlogic ISP2432 PCIe"/win=(0,8)
device = "Qlogic ISP2432 PCIe Fibre"
name = FG
driver = SYS$PGQDRIVER
adapter = PCIE
id = 0x24321077
boot_class = DG
boot_flags = HW_CTRL_LTR, UNIT_0
flags = FIBRE, PORT, BOOT
end_device
$

The "QLogic ISP2432", a dual-port 4GB HBA and PCI-Express too, a shame
we can't use the hot-swap features of PCI-Express.

Yes, there might be some path
changes, but that is transparent to applications and end users.

Sure it's transparent in terms of availability. In terms of performance
it's not in a lot of environments.

If you've balanced for performance reasons a small number disks on to a
specific HBA, that fails and gets the paths get pushed off to another
HBA, and they stay there (or can only be moved to other busy HBAs)
until you can drop the box, your application can certainly notice.

Of course, the answer is to simply to buy more HBAs, being that you
know you can't hot-swap/add in new ones.

So yes one can wait for the users/batch jobs to finish, then drop a
node, but it's not ideal and customers are left having to puchase more
hardware to mitigate for these times.


That's what mission critical Customers do as part of their base design.
In most Cust environments I have seen, normal users tend to logout at
5-8:00pm or they get disconnected for security reasons i.e. forgot to
logout before heading home.


I'm talking about trading systems supporting users and markets all
around the world. 9-5 local time isn't what it's about.

I'm more than familar with running active-active clusters and being
able to drop a node, my issue is the hit while one is waiting to drop
it. More hardware (which costs) helps here and can mostly solve the
problem, but hot-swapping would be a nice option to have too.

Alex

.

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