What is sfd

[Takashi Sekine]

Hi.

What is "/sbin/sfd" daemon on HP-UX 11i?
I don't see the sfd daemon in "ps -ef" list, before HP-UX 11i(11.0, 10.20 etc.)

* What is the role of sfd?
* Can I stop sfd without any side-effect?

Regards.

[S.K. Chan]

It's run from init, see the entry in /etc/inittab.
sfd:123456:respawn:/sbin/sfd
I think it is some kind of a daemon that is use to create device file. The reason why I say that is because if you do a strings on the file you can kinnda guess basically what it does.
# strings /sbin/sfd | more
One more thing I noticed is the file /etc/sfd.pid which contain the PID of the sfd process. Since sfd is started from inittab file, killing it would be no used as it will be restarted from /etc/inittab. My advice is to leave it alone.

[S.K. Chan]

I found more information .. apparently there is a patch for sfd and in that patch it mentioned about creating device file for remote disk (in SAN environment for example). Hope this clarify you're question about side effects of disabling it.

Patch Name: PHCO_23920

Patch Description: s700_800 11.11 sfd(1M) patch

Creation Date: 01/11/06

Post Date: 01/11/16

Hardware Platforms - OS Releases:
s700: 11.11
s800: 11.11

Products: N/A

Filesets:
OS-Core.UX-CORE,fr=B.11.11,fa=HP-UX_B.11.11_32/64,v=HP

Automatic Reboot?: No

Status: General Release

Critical:
Yes
PHCO_23920: OTHER
The "sfd" daemon may fail to start without this patch resulting in device special files not to be created for dynamically installed remote disks. As a result these dynamically installed remote disks
will not be accessible from user space commands and applications.

Category Tags:
defect_repair general_release critical

Path Name: /hp-ux_patches/s700_800/11.X/PHCO_23920

Symptoms:
PHCO_23920:
1. JAGad37868 / SR 8606168590
/sbin/sfd fails to start and logs the error message "sfd[]: pstat failed: Value too large to be stored in data type." to syslog.log.

Defect Description:
PHCO_23920:
1. JAGad37868 / SR 8606168590
The /sbin/sfd daemon fails to start, when the /etc/sfd.pid file contains a pid that does not correspond to the sfd process. This happens due to improper error handling when a 32 bit sfd daemon is run on a 64 bit OS.

[Takashi Sekine]

Hi, Chan.
Thanks for your information.

> I think it is some kind of a daemon that is
> use to create device file. The reason why I
> say that is because if you do a strings on
> the file you can kinnda guess basically what > it does.
> # strings /sbin/sfd | more

mmm...
It seems
* install special file using "insf"
* "edisk", "ectl", "eautoch", "etape"
... driver name??
TYPO or alternative driver of
sdisk, sctl, autoch, stape ???
* Look or Modify "/etc/ioconfig" file
through "/dev/config"?

I have a question (once more :-)

Q: WHO(application or command) use /sbin/sfd,
directory or indirectory?


> I found more information .. apparently there
> is a patch for sfd and in that patch it
> mentioned about creating device file for
> remote disk (in SAN environment for
-------------------------------

Like a "CommandView SDM"?
# or SAN Manager?

> example). Hope this clarify you're question
> about side effects of disabling it.

> Patch Name: PHCO_23920
>
> Patch Description: s700_800 11.11 sfd(1M) patch

[S.K. Chan · Accepted solution]

From my understanding, sfd (special file daemon) is ONLY used to manage the creation of device file for remote devices (like a SAN environment). Because of the dynamic nature of these remote devices (only create the device when an application wants to access it), it has to be managed in such a way that if sfd daemon dies, it is able to restart itself from /etc/inittab. If it were to be started in the usual /sbin/init.d startup method, when sfd dies the administrator will have to start it up manually. So to answer your 1st question, I would say it is used by any application that makes a request to the kernel to create an "ad-hoc" if you will device file for remote access.
For your 2nd question, yes I would think SDM relies on sdf (on the clients end) to manage the creation of these remote device files. I hope my explanation is clear to you :)