[Leaplist] Power mitigation, diskless v. truly thin, virtualization and/or remote -- WAS: Scanner Setup Help?

Fri Jul 24 14:29:27 EDT 2009

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I haven't had any trouble with using Linux as diskless.  I mostly run
Gentoo which everyone says is hard and complicated but all I had to do
is enable the proper kernel options and it worked.  I do not know if
their genkernel would have already had them enabled or not as I don't
like generic kernels or initrd.  I did setup a diskless Ubuntu 8.04
desktop that I allow guests to use for internet access and it worked
flawlessly as well.  I essentially just installed Ubuntu to a hard
drive, copied it to my server, changed the fstab, and rebooted.

I have run diskless on a 100Mbit network.  It is tolerable but it is a
bit slow.  Upgrading to gigabit is certainly recommended and it isn't
that big of an expense. Last year I upgraded my switch to an HP ProCurve
1800-24G Managed Ethernet Switch which is a good managed switch that can
do bonding and VLANing (yes I actually use both features).  It only cost
me $350 new and it consumes less than half of the power as my old
100Mbit switch.  It doesn't make any fan noise either unlike my old
Baystack 450 or my old Cisco Catalyst 3500XL.

As far as network cards go I prefer to get the Intel e1000 PCI cards as
their Linux and BSD (em driver) are both excellent and their PXE BIOS
(which is an Intel standard) is also excellent.  I haven't looked at any
PCIe cards yet because the computers I have with PCIe slots had
integrated gig-e chipsets that also had PXE support which was good
enough.  I believe the Intel cards were about $30 each but I didn't
really need many of them.  All my existing cabling was CAT5e so I didn't
have to worry about upgrading that either.

I am hopeful that the new cachefs subsystem in 2.6.30 will make much of
this irrelevant.  Soon you will be able to run NFS with a local cache
that will fix most of the performance complaints.  I foresee using older
1-4GB USB thumb drives as NFS accelerators on diskless systems.

Richard F. Ostrow Jr. wrote:
> A major version of "diskless" is that you spend real money getting a nice,
> highly redundant file server, and the client machines benefit from the
> redundancy built into the file server - ie, they don't need expensive RAID
> cards or anything similar. Of course, doing this for a desktop system
> probably isn't a good idea... 100MBit ethernet will only get you 10-12
> MBytes/sec, whereas a local hard drive will get you a 10X performance
> increase.
> 
> Personally, I utilize a master RAID server with real redundancy hardware
> (poweredge 1650 with 3 1TB SATA drives connected to a RAID-1 with 256M
> battery-backed RAM, as well as 768M ECC registered RAM, lights-out
> management, etc... all for ~$715) ($150 server, $75 lights-out management
> module, $80/drive, $250 RAID card). One drive is configured as a "hot
> spare", meaning it will automatically reconstruct the array in the event
> of a failure (buying me some time to fix it before another drive fails,
> which DOES and HAS happened (killed my last array)). Note that as of
> today, you can get 1.5 TB drives for $90 each.
> 
> To this, I connect my mythtv backend, which boots off of NFS to take
> advantage of the redundancy... and then tosses it out the window by using
> a software RAID-0 for the recordings across 3 1TB hard drives (so the
> system is fault-tolerant, but the recordings are highly susceptible).
> 
> Unfortunately, my experience thus far has been that linux only barely
> supports diskless systems, and frequently breaks that support for lengthy
> periods of time with kernel updates and baselayout updates. For example, a
> recent kernel update removed TCP packet support from NFS... which causes
> problems on my switch (admittedly, not a linux problem, but a switch
> problem... but using TCP packets fixed it).
> 
> Personally, for low-power systems (of which I have three), I use solid
> state over CF cards with a Via architecture (usually C7 CPUs). These have
> high temperature tolerances and very low power consumption... they've been
> running in my garage without A/C or ventilation for 1.5 months thus far.
> Basically, these are simple data processing machines (email, web server,
> proxy (purely in RAM, not in flash), bind9 server, etc) that don't need
> tremendous amounts of storage... or if they do, they can tie in over NFS
> to my file server.
> 
> On Wed, July 22, 2009 11:33 pm, Bryan J. Smith wrote:
>> Kevin Korb wrote:
>>> I think it is better to centralize storage and then make
>>> desktops diskless whenever possible.  Cuts down on the noise,
>>> heat, and power consumption.
>> Diskless or truly thin (remote execution)?
>>
>> Also remember that a typical 2.5" drive only uses 2-2.5W of power,
>> far, far less than even a typical, low-end chipset, let alone the
>> 12-20W of a typical 3.5" drive.  Even 10-15,000rpm 2.5" drives use
>> less power than commodity 3.5" 7200rpm and even "green" 5400-7200
>> variable 3.5" drives.
>>
>> The cost savings is really in the TCO more than power.  I've been
>> through this ROI game with numerous fiscal and retail customers
>> over the last half-decade.  Typical PC TCO is $500 just on the
>> servicing, which makes diskless and, even more so, thin clients
>> a major sell.  The power difference is less than 1/10th that.
>>
>> In all honesty, running with ARM instead x86 (instead of Atom as
>> well) is far, far more of a cost saver.  There are several new
>> NAS appliances hitting the market now that are a low-power ARM
>> with dual-2.5" (not 3.5") bays.  Small in size, and they run on
>> 12V @ 2A, typically sub-20W total.
>>
>> Jason Boxman wrote:
>>> It's all on the server(s).  The workstation is just RAID 1.
>>> I like to keep virtual machine storage local to my workstation.
>> People confuse virtualization and remote desktop.  No one advocates
>> virtualization over a remote mount.  However, virtualization providing
>> a remote desktop is a whole different story.  ;)
>>
>> Red Hat bought the upstream maintainer of KVM for more than just KVM.
>> Although control of a major upstream componen tlike KVM is trademark
>> Red Hat, especially when the vendor is dabbling with proprietary
>> software (and Red Hat wants to bring a quick and complete end to that).
>>
>>
>> --
>> Bryan J Smith          Professional, Technical Annoyance
>> b.j.smith at ieee.org    http://www.linkedin.com/in/bjsmith
>> --------------------------------------------------------
>> I don't have a "favorite Linux distro."  I use, develop
>> and support community efforts, often built around Linux.
>> Technology and solutions are my focus, not dragging in
>> assumptions, marketing and other concepts which dominate
>> non-community developed software, which I left long ago.
>>
>> --
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>>
> 
> 

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	Kevin Korb			Phone:    (407) 252-6853
	Systems Administrator		Internet:
	FutureQuest, Inc.		Kevin at FutureQuest.net  (work)
	Orlando, Florida		kmk at sanitarium.net (personal)
	Web page:			http://www.sanitarium.net/
	PGP public key available on web site.
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