On Thu, 11 Aug 2011 20:42:46 -0400 Robert Heller wrote:

Almost all modern disk are S.M.A.R.T capable. What this means is that various information about the disk, mostly relating to its health can be monitored. This includes things like sector errors. If smartd is running root will get E-Mail if/when something (however minor) happens to the disk.

As smartd isn't running in the default Centos configuration, where does palimpsest get its information? Is it a self-contained program that doesn't require smartd or is something else happening behind the scenes?

On Fri, 12 Aug 2011 04:05:47 +0000 Joseph L. Casale wrote:

I think you misunderstood the first reply: smartd, as in the init script is a means to alert root of pending issues, _it_ doesn't present the data, _that_ init script simply checks it and reports it. You don't need it running to make the data available, the attributes exist in the device.

Which still doesn't answer my question. Perhaps I'm wording it poorly -- I'll try again:

I load palimpsest and click on the entry for my hard drive, then click on the button labelled "SMART Data" and I see this on the first line of the window that opens:

Updated: 14 minutes ago

My question is, what happened 14 minutes ago? I didn't do anything 14 minutes ago, so something apparently ran in the background and updated that data. What is that something and how often does it run?

At Thu, 11 Aug 2011 22:24:23 -0600 CentOS mailing list centos@centos.org wrote:

On Fri, 12 Aug 2011 04:05:47 +0000 Joseph L. Casale wrote:

...

I think you misunderstood the first reply: smartd, as in the init script is a means to alert root of pending issues, _it_ doesn't present the data, _that_ init script simply checks it and reports it. You don't need it running to make the data available, the attributes exist in the device.

Which still doesn't answer my question. Perhaps I'm wording it poorly -- I'll try again:

I load palimpsest and click on the entry for my hard drive, then click on the button labelled "SMART Data" and I see this on the first line of the window that opens:

Updated: 14 minutes ago

My question is, what happened 14 minutes ago? I didn't do anything 14 minutes ago, so something apparently ran in the background and updated that data. What is that something and how often does it run?

The disk's *firmware* updated itself. So long as the *disk* is powered up and spinning, its *firmware* is 'running' (or runs when the disk is accessed or something like that). Modern disks are a long, long way from the simple MFM drives of the 1970s (which presented little more than a buffered interface to the drive mechanism and read/write heads to the host controller -- eg little more than a simple floppy disk drive) -- modern disks have actual embedded micro-processors on them doing various stuff, including monitoring and logging things like sector errors, drive temp., and so on.

Appearently, palimpsest does some of what smartctl does: accesses the SMART data on the drive. This is completely independent of smartd. Smartd is a daemon that runs in the background and periodicly accesses the SMART data on the drive(s) and if there is some sort of notworthly problem or condition (too hot, bad sectors being remapped, etc.), it logs it and sends an E-Mail to root@localhost.

On Fri, 12 Aug 2011, Robert Heller wrote:

The disk's *firmware* updated itself. So long as the *disk* is powered up and spinning, its *firmware* is 'running' (or runs when the disk is accessed or something like that). Modern disks are a long, long way from the simple MFM drives of the 1970s (which presented little more than a buffered interface to the drive mechanism and read/write heads to the host controller -- eg little more than a simple floppy disk drive) -- modern disks have actual embedded micro-processors on them doing various stuff, including monitoring and logging things like sector errors, drive temp., and so on.

So does accessing some of the smart data cause any disk i/o at all, or is this all done from directly firmware?

Kind Regards,

Keith Roberts

----------------------------------------------------------------- Websites: http://www.karsites.net http://www.php-debuggers.net http://www.raised-from-the-dead.org.uk

All email addresses are challenge-response protected with TMDA [http://tmda.net] -----------------------------------------------------------------

On Fri, 12 Aug 2011, Robert Heller wrote:

*snip*

...

...

The disk's *firmware* updated itself. So long as the *disk* is powered up and spinning, its *firmware* is 'running' (or runs when the disk is accessed or something like that). Modern disks are a long, long way from the simple MFM drives of the 1970s (which presented little more than a buffered interface to the drive mechanism and read/write heads to the host controller -- eg little more than a simple floppy disk drive) -- modern disks have actual embedded micro-processors on them doing various stuff, including monitoring and logging things like sector errors, drive temp., and so on.

So does accessing some of the smart data cause any disk i/o at all, or is this all done from directly firmware?

Depends. Some of the SMART information is stored on special sectors of the platter (sectors that are not part of the sectors available for normal use). Some of the information is fixed burned into the (E*)ROM(s) (eg serial numbers) on the disk's logic board and some information is 'live' (eg current disk temperature). There IS I/O between the host system and the disk's logic board.

Thanks Robert. Reason I ask is because I'm using GKrellM to monitor my HDD temperatures. So I just wondered if querying the HDD temps to often would create more disk i/o ?

Kind Regards,

Keith Roberts

----------------------------------------------------------------- Websites: http://www.karsites.net http://www.php-debuggers.net http://www.raised-from-the-dead.org.uk

All email addresses are challenge-response protected with TMDA [http://tmda.net] -----------------------------------------------------------------