Re: You can dial on a tone line...
Tone dialling usign a whistle?
As in Capn' Crunch
120 posts • joined 14 Mar 2010
Its worth explaining what Panasas is. It is a 'storage cluster'.
Each storage blade int he rack is an independent computer - with a processor, RAM, flash storage and/or spinning disk storage.
Small files are kept in two copies, each on a separate blade.
Larger files are stored across a set of blades.
So if you lose a blade, the blade is replaced and a new blade is automatically installed.
Joerg, I have installed and run Panasas systems.
It is not a RAID 6 storage array.
"What Panasas’ RAID 6+ does is to end the default rebuilding of an entire failed drive and only rebuild the damaged data components.It can do this because, at heart, it is an object-based parallel filesystem. "
ie you rebuild the objects which are on the blade which has failed (or indeed you can move data off a blade which is suspected to be nearing failure).
Small files are stored RAID 10, and larger files at RAID 5 or RAID 6 with this new array.
Kurt, and The Mole
I agree abotu getting wheelchair taxis out 'in the burbs' as I've said above.
But let me speak up for public transport in London - which is bloomin marvellous on the whole.
All bsuies have wheelchair ramps, the DLR and a lot of the Jubilee Line is completely wheelchair accessible. As is a lot of the Overbround too.
AC, I honestly tried that one Sunday not so long ago.
Radio Taxis wouldn't help.
Local cab firm in Eastleigh saud 'Oh yeah - we do have a wheelchair capable cab. But the bloke who runs it is not working today'
My point really being that you can't just assume that taxi transport will be available if you are accompanying someone in a wheelchair. You really have to plan ahead and make SURE.
Like the night I booked a wheelchair equipped taxi to call at a hotel to go to a big do.
Sure enough Mr Private Hire turns up in a normal saloon - with no wheelchair facilities.
They often just try to chance their arm, resulting in a vastly delayed journey or no journey at all.
"Taxis are expensive, especially wheelchair equipped taxis, require planning to use, have limited flexibility (how long will your shop take), and require depending upon a total stranger"
Almost completely agree.
London black cab drivers are diamonds, and as they are all wheelchair ramp equipped are fantastic and helpful. (Reference the Uber app articles - minicab drivers are not required to have wheelchair access).
But outside London?
Just try getting off at Southampton Parkway when there are engineering works and try to get on a taxi. Oh - you have a wheelchair. Errrrr.... no go.
Or just arrive at Southampton Central where there are a whole line of taxis outside -none of which take wheelchairs. Ho hum.
Oh yes. Re. the comments above, I agree about the 'voices in the head'
I once installed an Oracle RAC cluster in an English university (OK it was UMIST).
I did ask if there was enough power for it before turning it on.... Oh yes I was told.
Sure enough, power up the racks and...... silence. Except for the beeping of UPSes and the running of IT staff feet towards the machien room.
"There were the days when Windows NT had a MIPS port, "
Yup. NT was going to run on everything from your desktop PC, up through servers and onto the big supercomputer iron.
Remember that Unix was not prevalent - it was something for academics.
True IT shops ran VMS (or IBM mainframe MVS or whatever).
The world was meant to move to NT, on several architectures.
Microsoft killed that one by discontinuing the MIPS port.
"yet there wasn't a single Visual Workstation to be seen, and, to this day, I've never seen one in the flesh)"
I worked in a visual effects/animation company in Soho arround that time - many Octanes and several large Origin 2000 systems - nice! Some Fuel workstations if I remember right.
I remember we got one or two of those Visual Workstations - argghhh. They were so non-standard.
The PCI bus ran at a different voltage than any standard PC, so you couldn't put off the shelf peripheral cards in the thing.
you are also right about the Linuxclusters.
Vic, talking about drugs and the placebo effect,
is there not a great influence on the surroundings, the company and the expectations when drugs are taken?
I remember reading about a study where students were given alchohol, or a drink tasting the same but with no alcohol at all. Most reported feeling 'drunk''
And no, I'm not going to repeat the experiment by dropping some acid and convinginc myself that it is a bit of blotting paper which will do nothing to me!
TRT ukgnome - your statements are not contradictory.
Read Ben Goldacre's book Bad Science. Ben is no fan of homeopathy.
However he discusses it in the book - it works as well as a placebo, because the practitioner takes time to take a medical history, and gives you something for the complaint.
I agree 'the something' is water. Or a sugar pill.
So vefore you get me wrong - homeopathy is completely useless if there is something serious wrong with you (and indeed it can stop you seeking real treatment and is therefore actively dangerous).
But in the cases of minor conditions it works as a placebo.
That episode is in (I think) Francis Spuffords book 'Back Room Boys'.
the SR71 pilots tell of how they are indeed at 80000 feet over Cuba, wearing pressure suits.
They look down on a Concorde below and reflect that the Brits/French have engineerd an aircraft which can fly up there with them, at high Mach, with people inside in shirtsleeves drinking Champagne.
Oh, and if you haven't read it, Ben Richs book 'Skinkworks' is fantastic
The U2 is indeed a Starfighter body with long, thin wings.
Power over Wifi?
There was an article on El Reg about mobile phones which woudl charge using power gathered from radio transmissions - ie the everyday AM and FM
So truth is stranger than fiction.
Quick Google turns up:
Peter, I completely disagree with you.
I, for instance, work in High Performance computing.
I manage and monitor several large systems which run engineering simulations 24 hours a day.
These are housed on premises, in server rooms.
I for one see that the cloud is laready having a major imact on HPC, and will do so in the future.
I don't want to empire build - in fact I would rather NOT have to look after hardware at all - and get on with the interesting stuff. There will ALWAYS be a place for the folks who understand how that data gets in/out to those 'connected apps' you so glibly talk about - when that magic data doesn;t get to your fridge you need someone who can be arsed to learn about IP netowkr, traceroute, packet sniffers and all those other deathly boring things (to normal people I mean).
Its not empire building to want to look afterm diagnose and improve the performance of equipment.
Alistair, that is a damn good article.
I agree re. the stress.
And also re. the brain surgeon analogy - we celebrate people with money making skills, or celebrity, but we leave our best and brightest scientists shockingly underpaid.
Seriously - I looked at jobs recently in two top research labs in the Cambridge area. Rates of pay less than what I get now, so I couldn;t consider them.
Also I have a point - if there IS such an IT skills shortage, why aren;t companies shovelling money at IT types? Why aren't we being offered telephoen number salaries and huge bonuses like bankers?
"Very long term archival requires recycling tapes every 5 years as well as tape migration projects to new formats, "
Magnetic disks don't last that long either.
I have one array which is coming up for five years old - disks are regularly failing on it. Still getting didks under a support contract which is fine.
I don't think you should expect ANY medium to last for many years (except maybe acid free paper).
Remember thought hat LTO tapes guarantee being able to read from two (?? or more) generations back of tape drive, ie LTO5 will read LT05
I've put my foot in it here - cue war stories of how old tapes are NOT readable.
I agree with you regarding Silicon Glen.
There is an HP office still in Erskine.
IBM Spango Valley is winding down,a s reported in the Register.
SUN in Livingstone is long gone AFAIK - I remember visiting there quite a lot to assemble and test Beowulf clusters.
There is an Amazon R&D lab in Edinburgh, which sounds fun.
As an expat Scot who would like to return, there is a paucity of opportunities.
Regarding RAID scrubbing, only once in five years have I come across this problem - ie. a disk failing, and a second disk on a particular storage array flagging up a bad block.
I was already running a regular RAID scrub every four weeks, and upped that time to every two weeks.
Good article Storagebod.
There was a recent Guardian article on growing older and ageism in IT,
well wort a read. Sorry I can;t find a link at the moment.
And thankyou for the link to Etherealmind - I happen to be doing som enetwork diagrams at the moment, and his book on Visio network diagramming looks very useful!
I am buying a copy.
I used a real IBM 3090 mainframe when I was a PhD student.
Real 3270 terminals with the proper spring action keyboard and a twinax connection from the office down to the server room.
When we got an Ethernet connection for that machine guess what arrived?
An IBM PC in a box, complete with ESCON (?) channel adapter card and chuge cables, plus an Ethernet card. Yep, the mainframe used a lowly PC as an ethernet 'bridge'.
Finding people with skills in "large-scale operations at a global scale" is "really rare," he told The Reg in San Francisco on Thursday, and worried it may become almost impossible to recruit such techies.
Well if that is the case, why aren't hosting companies shovelling money at sysadmins?
I wish they were...
As a sysadmin who looks after large scale HPC systems, I do not see cloud as a threat to my job.
Whether or not the kti is actually on my premises doesn't threaten my job.
Companies will STILL need people with a clue about networking - ie how in the heck does this magic 'data' get to and from the 'servers' - ie people who understand and can troubleshoot layer 2 and layer 3 problems.
Still need people who have a clue abotu exactly how processes are run on a system, and about performance measurement and right sizing of systems.
As a for instance, I just gained a 15% speedup on one of your systems just by having a chat with someone about how he was running things, and made a simple suggestion (turning off hyperthreading actually). My experience showed through there.
Youc an configure Linux to recognise the Bluetooth ID of your mobile.
If the mobile moves out of range the screen is locked.
"(my preferred versions of openSUSE at time of writing, for example, would be 11.4 or 12.2 but both are coming to the end of their lives now) it is common to find that distros prefer you to keep up to date and provide little support for older versions."
Well - you really mean the 'community' distros like OpenSUSE and Fedora here.
And to be honest the line from OpenSUSE is that you can easily upgrade - just set your repositories and to a zypper dist-upgrade.
But perhaps of more relevance - check out the SuSE Evergreen project.
That is keeping older distros alive by providing updates. So you DO have support for older versions.
"At the levels of precision these colliders are operating, I'd have thought that building them in the Alps might introduce anomalies and gravitational distortions"
Well - the LEP accelerator was so finely instrumented that it detected earth tides for the first time.
There was a small chaneg in the beam tuning noticed twice a day.
Investigations showed this was due to earth tides - like ocean tides, but the earth is moved (*)
(*) Yeah, yeah. Particle physicists make the earth move!
Well yes, you do have track junctions and marshalling yards.
CERN has an accelerator complex - the older, lower energy accelerators produce the original particles, which are then injected into the larger rings. So yup, you have a points system like a railway.
The SPS began operation in 1976 and is still used as the injector for LHC.
Better latency than a TCP connection, by using Infiniband and RDMA.
You're looking at 1 microsecond latencies.
(Of course you can run RDMA over 10Gbps ethernet also)
"One would hope it would cost a bit less to maintain and run than actually sourcing a brand new one."
Well... maybe not.
As machines become older, it gets harder to source the parts - particularly DIMMs and CPUs.
So HPC manufacturers ask increasing amounts to keep older machines under maintenance.
Of course it is in the interests of manufacturers to sell you new machines.
In my experience it is the DIMMs which will go faulty most often on a machine such as this.
"Except for the rather important question of "why didn't all this matter/antimatter just annihilate each other shortly after the Big Bang when it was all so close together,"
The reason is called CP violation - and is one of the reasons why high energy physicists study b quark decays so closely. (I studied high energy physics and was a member of a CERN experiment).
All particle interactions are invariant under the operation CPT (charge conjugation, parity and time reversal). So all reactions should run at the same rate, forwards or backwards.
However some reactions, such as b decay, exhibit an asymmetry under CP reversal. Which means they must have a different reaction rate (T).
CP is the operation to turn a particle into its antiparticle, so CP violation means that some particles and antiparicles ahve different decay rates.
I hope to goodness I have remembered the above correctly, and I stand to be corrected when a card carrying physicist comes along.
Nate, you make a good point regarding the overhead that virtualization takes, which is decreasing.
For HPC, I beleive that Docker will have a big future - packaging up containers to run a specific application, with its associated libraries and running them on VMs.
Also HPC workloads perform when you have CPU pinning - ie processes run on an allocated core and aren;t moved around by the OS (you want all those caches fileld nicely, and not having to repopulate them). I already run cpusets on an HPC ssytem I manage, and see cgroups as an extension.
"That said, dumping nitrogen into the coolant reservoir might be an idea for an emergency "we need 120 seconds to shut everything down nicely" solution."
But you should have some sort of thermal monitoring anyway - hopefully shutting down automatically when the temperatures rise above a set threshold.
That's where old style mainframe 'halls' were good - high ceilings, lots of thermal mass.
BTW, Trox in the UK already do produce cooled doors cooled by CO2.
"or maybe the 'victorian' eggheads dont have a problem with sudden outage, interupted computation or loss of data. They can always go to the beach!"
Look at my comment re. UPS for the storage - that is very desirable and yes data corruption is not at all wanted.
But re. sudden outage, HPC jobs can and will have this. The job should write a checkpoint solution every so often (*) and could be re-run from the last checkpoint if it fails.
These workloads consist of simulations - if one of the blades running the simulation fails, the whole run is likely to stop anyway.
(*) that is an interesting problem in itself -and is one of the reasons HPC likes big fast storage.
Remember - these are HPC systems. Hi Chris!
Typically they draw a large amount of power per rack - but jobs can be halted and checkpointed if you need to turn the system off. It is not critical that they are up 100% of the time.
(Making that clear - it is GOOD that they are up as close to 100% but its not business critical and jobs can sit waiting in the queue to run later).
On an HPC system you woudl tend to be more concerned about having UPS for your storage and head nodes (login / provisioning nodes).
That said, a UPS does give you power smoothing, so for that reason there are UPSes on all nodes on the systems I look after. However we don't expect a long runtime - there is sufficient time to checkcpoint jobs and shed the load by switching compue blades off.
High capacity tape DRIVES aren't cheap - the economies of scale come in when you have a library with hundreds or thousands of tapes, most of which are sitting there consuming no power.
So you are using an expensive device to access multiple 'cheap' devices (not that LT0 tapes are that cheap).
In the past, I would have said that the consumer equivalent for backups would be a writeable DVD - but hard drive capacity has of course far outstripped DVD capacity.
You are right though - there would be a market for a durable, high capacity backup solution for home use which could simple be parked on a shelf for years.
Alan, what flaws have you found in DMF?
Certainly satisfies the requirement for everythign going to tape at least twice - you can specify that easily, and also look for any files which somehow have ended up on only one set of tapes. You can easily use disk as a cache layer (which I do).
Indeed when the AWS annoucement of virtual tape libraries on their storage gateway came out it set me thinking on a configuration where you have a local tape library, with the primary copy, and use Amazon Glacier for the second copy. Cost aside, you have disaster recovery.
Barrage balloons brough down aircraft as they held up a steel cable, with a weak link at the bottom.
If an aircraft struck the CABLE it would break off and drag the aircraft down.
I suspect an octocpter thing would simply bounce off any cable or balloon.
Sorry - don't mean to be all technical and snidey, and I've never even seen a barrage balloon.
Just think it is interesting to learn the real mechanism of how they worked.
Nigel 11, you have it right regarding NUMA systems.
And as you say quite run-of-the mill multi-CPU motherboards are already NUMA systems.
And there are much bigger NUMA systems out there!
Install the absolutely great tool 'hwloc' from the OpenMPI project
You can get a graphical display of how your system is laid out.
Assuming you are running Linux, install the 'numactl' package and use
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