Hi all,
I would be very interested in getting feedback about kernel 2.4 usage.

Please, please, I do not want this thread to degenerate into a useless

flamewar or "mine is bigger" discussion. For this reason, I would like

that participants reply privately to me so that this mail does not turn

into a thread.
I know 2.4 is still used in a lot of sensible areas, although far less

than 2.6 nowadays. At least I know that several appliance makers/sellers

still use it in new products, and even very old versions sometimes. What

I'd like to estimate is the way it is used, if it is systematically

patched with local add-ons, frequency of updates (if any), etc... so

that I can adapt my process if needed. For instance, I don't release

any -rc for stable releases because I'm convinced that nobody will ever

test them, but I have no problem being proved wrong.
If I get enough replies to build up a statistic synthesis, I'll try to

summarise it (eventhough 73% of statistics are all made up :-) ).
This "poll" is not meant to dictate what will get merged next (we're in

feature freeze anyway), but it helps me know your usage better, to try

to serve you better. Also, if a majority of people report the same

problem or lacking feature for which a trivial fix is know, it can be

studied.
Basically what I'd like to know is the following. You can use the proposed

responses as a guide, but they're not mandatory. Also if possible and adapted,

please report number of concerned units :
1) where do you use it ?

   - PC turned into network equipment (router, LB, BGP route reflector, ...)

   - security equipment (firewall, vpn, ids/ips, traffic analyzer, ...)

   - proxy services (proxy, smtp relay, reverse-proxy, anti-virus/spam, ...)

   - storage/directory server (NFS, LDAP, logging, ...)

   - multi-function server (proxy/fw/nfs/mail/...)

   - monitoring / remote access

   - desktop/workstation

   - laptop (if recent, what model ?)

   - dedicated appliances (that you may be designing/selling)

   - soho...
[ message continues ]

Hi all,
I've tried to summarize the usage reports I got for kernel 2.4.
[ Note: some of the responders asked to be notified when I send the

  results, so I've Bcc'd the responders so that they can get the

  results without being polluted by potential responses.            ]
About 22 useful responses. It is not possible to report accurate numbers

because most participants did not themselves have accurate numbers. I

would say that based on the responses (and a few cases I know), 2.4 usage

approximately follows this distribution :
 - old recycled laptops at home, or PDA/thin clients - ~5%

   They rely on whatever kernel managed to boot on them, then they never

   got updated anymore. Security generally not too much of an issue, no

   plan to update to newer 2.4, let alone 2.6. The hardware will die first.

   Sometimes a few patches were added to support one particular component

   or enable one feature specific to the use case. These boxes have the

   lowest level of criticity.
 - desktop PCs, monitoring stations - about the same as previous ones, with

   an increased level of criticity. Generally users have not upgraded simply

   because "it works". Those are systems with known fixed hardware and usage

   pattern. Most often they serve as X11 terminals and/or browsers, and do

   not require many updates. They cause trouble to the user(s) when they

   die and no benefit is expected from an upgrade to 2.6. Future installation

   (same or replaced hardware) will generally be on 2.6.
 - general purpose servers : regularly updated - about 50%.

   The pattern is most always the same. A lot of services are installed,

   among which WWW, Mail, DNS, Samba, NFS. The server never experiences

   any outage, and a moderate amount of people would be affected if a

   problem happened. Almost always up to date with latest 2.4. Reason

   for not upgrading to 2.6 generally is lack of need and time, as well

   as risks of regressions which would get a lot of users angry. Users

   per server a...
[ message continues ]

Just a note that some "how many" and "which version exactly" data is

available from [1] which is generated from data users send through a

cron job with data from nearly 5000 machines reported during the last

60 days.
When clicking on a version (e.g. "2.4.27") you can also see which of

them are distribution kernels.
Kinda shocking that 14% of these machines are not running kernel 2.6 ...
Considering how this data is generated it obviously shows only part of

the picture, and your survey will hopefully bring data what we could do

for making kernel 2.6 more attractive (not meant against your work, but

we should aim at bringing users to 2.6).
cu

Adrian
[1] http://counter.li.org/reports/systemstats.php
-- 
       "Is there not promise of rain?" Ling Tan asked suddenly out

        of the darkness. There had been need of rain for many days.

       "Only a promise," Lao Er said.

                                       Pearl S. Buck - Dragon Seed
--

Hi Adrian,
I've already seen this one sometime ago, but realized that you will never

get stats from sensible systems there. For instance, none of my customers

running linux in production would ever accept to permit an HTTP communication

between any of their servers with another one on the need, and especially

when it comes to reporting stats about *their* versions.
Also, I recently realized that several high-grade commercial products still

ship with 2.4 in it. I even know about one which never said it used Linux,

running on MVL 2.4.2 :-)
Of course those ones do not care a dime about recent versions. But it looks

like the falling curve has reached a stabilization point, because such

products would have had hundreds of opportunities to upgrade. Reason why
100% agreed, and it's the orientation of the survey. At least 2.6.16 could

be a first step for those who need high code stability.
Speaking for my case, at Exosec we still use 2.4 a lot. Main reason is that

we are used to apply a lot of patches. And maintaining a kernel which does

nearly not change in 6 months is really a joy. I have already thought about

moving to 2.6.16, but I would have had to port my patches, and was not

satisfied by the crapp^Wold scheduler which caused real performance issues

for my workload. Since I would have gained nothing in this operation, it

was easier to stick to 2.4.
I'm waiting for other people's excuses now :-)
I'm really tempted by making a new attempt with 2.6.25, but let's let it
Cheers,

Willy
--

Hi Willy,
You might want to wait a bit more and pick a version which will end up

in either SLES or RHEL. These tend to be maintained for longer than the

other versions. For example SLES10 is based on kernel 2.6.16, which is

still maintained by Adrian (or at least was maintained for a long time

- I don't know what the current status is.)
--

Jean Delvare

--

A variation of the theme, which I as maintainer of some drivers in 2.6

heard by way of occasional questions on subsystem mailinglists or

off-list:  Kernel customizations for embedded systems in combination

with a custom userland.  Moving all this software over to 2.6 was not

considered worth the effort.
Another reason which I read here and there and don't know how real the

issue is:  2.6's minimum possible footprint is said to be unable to

compete with 2.4 for really resource restricted applications.
Could it actually be that 2.4 outnumbers 2.6 in embedded installations?
(I don't work with 2.4 myself and I don't know the domain of embedded

systems.)

--

Stefan Richter

-=====-==--- -=-- ===-=

http://arcgraph.de/sr/

--

On Tue, Apr 29, 2008 at 3:06 PM, Stefan Richter
Possibly.  However many embedded applications have real time

constraints so are using 2.6 these days.  Both vanilla and -rt patched

2.6 beat the pants off 2.4 in this area.
Lee

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