
Ask HN: In what condition, company will consider to use system other than x86? - mikewang
By that I mean Power and s390 specifically.
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detaro
If you aren't already in an ecosystem (mainframes or AIX), the obvious
question is: what does a different architecture offer you, how well is it
supported by what you use and and what does it cost you to migrate. In
reverse, typical benefits of x86 are a) wide support in nearly all software,
b) multiple suppliers of chips, c) large number of suppliers of systems at all
kinds of sizes and specializations.

POWER systems have high memory bandwidth and can take really large amounts of
RAM. You're limited to what IBM sells then, but the x86 market at that top end
also isn't that large and less standard: Many companies will sell you 1-2
socket servers with 64-512 GB RAM, but if you want >3 TB its getting thinner
there too, so also less benefit from using x86. So POWER is an option there,
if running Linux the difference for sysadmins isn't that large. And e.g. SAP
supports it for their HANA in-memory database, so enterprises might buy them
there. At the same time, lots of enterprise software doesn't run on them, so
they're unlikely to fully migrate.

Then there's companies building their entire stack themselves and operate at a
large enough scale that some porting costs are acceptable if it brings them a
benefit. They'll always be looking at alternatives. Google is known to have
experimented with POWER systems. Cloudflare afaik is using some ARM systems
because they turned out to be the more efficient choice for them. At
Google/Facebook/... scale, it's likely also a signaling tool when buying:
Intel is more likely to give them what they want if there's a somewhat
credible threat of them replacing part of their systems with non-Intel.

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tgflynn
I don't think there's much competition between x86 and s390. You'll use the
later only if you're already an IBM mainframe customer and don't plan to
migrate off.

For Power vs x86 it probably matters a lot what type and scale of operations
you're at. As far as I can tell x86 typically has the better price/performance
ratio but then I think there are quite a few supercomputers that use Power so
there must be some advantages (probably mostly I/O related).

~~~
CyberFonic
The only Power based supercomputers I can think of are all from IBM. Does any
other vendor use them?

Power CPUs tend to power either iSeries (latest iteration of AS/400 - System38
etc) systems or AIX based. The large AIX systems use lots of CPUs, cores and
typically vPars - but I wouldn't call them supercomputers. Disk I/O is
generally FC attached SAN, i.e. performance is achieved through off-loading. A
typical SAN array contains gigabytes of caching memory, CPUs on each disk
drive with yet more RAM and multiple optical FC links to each node.

~~~
tgflynn
> The only Power based supercomputers I can think of are all from IBM. Does
> any other vendor use them?

Perhaps not but there are non-IBM Power systems available, such as those from
Raptor, as well as IBM Power systems primarily intended to run Linux.

Also I think Google has looked into running Power systems, but I don't know
that they have any in production.

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CyberFonic
I have worked for companies that used both. Based on those experiences:

Use Power RISC with AIX in established IBM user organisation that wanted to
run Unix software so we ported existing software to AIX.

Use existing s390 system running several core systems, to run Unix partitions
to deploy software already written for Unix in C.

I have never even heard of any company not already being an IBM account
migrating to either of those systems. The capital and operating costs are
typically far higher than for comparable performance x86 based deployments.
Technical staffing is much harder still.

~~~
mikewang
>I have never even heard of any company not already being an IBM account
migrating to either of those systems.

If this is true, this line may be another reply to my question.

~~~
tgflynn
There are certainly companies that have experimented with Power, including
Google, but I've never heard of any large migrations either.

One other consideration is that Intel chips come with closed source and
completely opaque logic embedded in the silicon, such as the Intel Management
Engine.

As I understand it Power is now a fully open source architecture and you can
get a system with fully transparent firmware (at least if you buy a non-IBM
system). Depending on your security needs and threat model that may be an
advantage, but I doubt it's a significant enough concern for most companies to
justify the lower price performance ratio.

