[AG-TECH] Advice sought on AG server upgrade proposal

Stanford P. pns at noc.soton.ac.uk
Wed Oct 13 12:11:37 CDT 2010


Hi
I am currently trying to put together a proposal to upgrade our rather
ancient Access Grid servers. I have looked through this list and gleaned
various bits of useful information about possible configurations. I would be
grateful for comments about any aspect below - apologies in advance for the
length of this mail.
 
Background:  we installed a pretty traditional room-based node about 6 years
ago  - a two-box HP workstation system running AG Toolkit under Linux,
XAP800, Sony EVI-D100 cameras using s-video into Osprey capture cards, and
using a NVidia quad-head display card.
The aim is to update the servers, but keep the XAP and the existing Sony
cameras for standard definition video feeds. If possible we also want to add
two HD feeds for future use, from the Tandberg Precision HD cameras we also
have in the room for H.323 videoconferencing (these can output
simultaneously on HD-SDI, as well as the HDMI connection we use for the
H.323 videoconferencing).
As well as Access Grid, we want to use this infrastructure with other
collaborative software such as EVO, or even to use Skype in a room-based
environment.  Although we have a strong preference to run things under Linux
(Fedora or RHEL), we will probably want to make the new server(s) dual-boot
to some flavour of Windows too so we can cope with any eventuality.
 
We¹ve found our current hardware to be very reliable, so for starters I¹ve
looked for updated versions of what we¹ve got rather than changing
everything in sight.
 
I¹m still undecided about the one box / two box question.  In support of the
two-box approach, I can understand the complication of the operator seeing
multiple VIC instances on a one-box system, rather than just having a single
instance on the display machine. Also, I do still wonder about the wisdom of
expecting one box to cope with (say) capture of two HD streams and 2 SD
streams, plus audio, plus quad-head graphics output and networking. That
seems an awful lot of i/o (translating to CPU load). However, for use with
EVO, both capture and display would need to be on the same machine (unless
you signed in on two boxes, I guess). In the end of course it will probably
come down to money.  Your current opinions are solicited on this issue.
 
New server(s): The HP z800 looks a pretty good spec, particularly when it
comes to i/o in the form of the number and type of PCIe slots ­ it would
seem to give some options for future growth, even on a one-box solution.
Also we mostly use HP for our other servers, so are generally comfortable
with their support.
 
Processors: I would prefer dual quad-core processors, but would welcome
advice as to whether this would be overkill, particularly in a two-box
solution.
 
Memory: I¹m assuming that memory requirements are not particularly great,
and that something like 12GB per box would be ample (memory is triple
channel on the z800, so for dual processors needs to be installed in sixes,
hence 6 x 2GB)
 
Disk: Similarly the disk requirements should be modest ­ we¹d probably keep
the Linux and Windows installs on separate drives for simplicity ­ ideally
I¹d like to mirror each OS on a pair of drives.  There seemed to be some
references to Linux on the z800 needing SAS rather than SATA drives for any
RAID config, but whether that applies to a straight RAID1 mirror I¹m not
sure.  At a pinch we could live dangerously and just have a single drive
(146 or160GB) per OS I guess.
 
SD video and audio capture: The initial need is to be able to support the
current 4  s-video feeds, and I was looking to use the Osprey 450e if
possible (though there seemed to be some doubt as to whether this was
supported under Linux or  VIC yet).   A second best might be the Osprey 440
(normal PCI).  Either should be able to do the audio capture too.
 
HD video capture ­ The Blackmagic cards seem to be the popular option, both
for AG and EVO. The ŒDecklink Duo¹ takes two HD-SDI inputs, which would seem
ideal for our system., and it seems to have a Linux driver. It isn¹t crucial
for it to be supported Œright now¹ in AG Toolkit / VIC, but it would be nice
to know it¹s on the horizon.
 
Graphics card:  One quad-head card supported in the z800 seems to be the
Nvidia Quadro NVS 450 ­ we¹ve previously used the similar PCI card with good
results. The current PCIe model outputs on DisplayPort connectors, which we
would have to convert to VGA.   An alternative could be two NVidia Quadro
FX580 cards, as suggested here:
http://www.arcs.org.au/index.php/tturnkey-video-collaboration/318-room-based
-turnkey-vc-system but I am not sure what the benefits would be compared
with the single card.
 
There¹s probably something else obvious I¹ve missed but this is long enough
already. 
 
Thanks in advance for any comments
 
Phil Stanford
National Oceanography Centre
Southampton, UK



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