[CentOS] how to control Hard Drive light from Linux?

Mon Jan 24 07:54:47 UTC 2011
Rudi Ahlers <Rudi at SoftDux.com>

On Mon, Jan 24, 2011 at 2:55 AM, John R Pierce <pierce at hogranch.com> wrote:
> On 01/23/11 3:24 PM, Jure Pečar wrote:
>> There's no real standard in hardware to play with leds. For example, you
>> can play witch num/caps/scrol lock leds on your keyboard easily, but
>> there's no such standard for cheap generic drive enclosures. Fancier ones
>> use saf-te, as others already mentioned.
> if this is an external SAS/SATA array, its highly likely it uses SES2,
> the successor to SAF-TE, or SGPIO (the successor to SES2) and again,
> SES2 usually appears as another 'scsi' device on the backplane, it
> should show up if you list all devices on the HBA.  alternately, SES2 is
> accessed via SMbus i2c commands.     SGPIO however, uses a special iPass
> connector and is only supported by specific HBAs that have the ipass
> interface which combines SAS and the SGPIO signals.
> I believe there are packages for both SES (sg-ses) and sgpio, and if you
> setup this stuff and properly configure it to match your enclosure,
> dmraid/mdraid should automatically set the LEDs.   the problem is,
> there's a lot to configure.  for instance, if your HBA has in fact this
> sgpio support, there's no standards for how the host talks to that.
> having never actually done this (we buy packaged storage from vendors
> who take care of this stuff for us), thats about all I can suggest.

Hi John,

Thanx, this is the info I needed :)

I'm looking into building low-cost NAS devices seeing as the
commercial stuff we already have are often on Atom or other
slow-processor based equipment and also very limited in many aspects.
Building it ourself, we could add faster CPU's, ECC RAM, better
network cards, industrial grade motherboards, etc and not be limited
to a vendor's software choice For example, one vendor has a good
product line, but don't have RAID 10 (we've been requesting this for
about a year and a half already). Another vendor doesn't have EXT4,
NFS or iSCSI multi-path support. And another vendor chooses to cap the
storage at a certain limit. Why, I don't know, but that's how they do
it. Only one vendor has 10GBe NIC support, but then you can only
install 1x 10GBe NIC per NAS. None of them has native ZFS support
All of them run a flavor of Linux, generally Debian.

So, now I want to look into doing this myself. 2U / 3U chassis with
redundant power supplies, industrial motherboards, server grade CPU
(some of these have notebook CPU's), ECC RAM, multiple 10GBe NIC's,
hot swap drive cages, etc and pretty much do exactly as they do.
SuperMicro, IBM, Dell & HP all have decent storage chassis so now it's
just a matter of getting the software to work nicely :)

I have looked at OpenFiler (very outdated), FreeNAS (a bit limited,
0.8 looks promising), Nexenta (very nice, but also very limited) and
just plain'ol CentOS for OS's for the NAS's but haven't found
something that could work as well as I like it to.

Kind Regards
Rudi Ahlers

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