[CentOS] ssacli start rebuild?

Thu Nov 12 02:04:49 UTC 2020
John Pierce <jhn.pierce at gmail.com>

in large raids, I label my disks with the last 4 or 6 digits of the drive
serial number (or for SAS disks, the WWN).    this is visible via smartctl,
and I record it with the zpool documentation I keep on each server
(typically a text file on a cloud drive).     zpools don't actually care
WHAT slot a given pool member is in, you can shut the box down, shuffle all
the disks, boot back up and find them all and put them back in the pool.

the physical error reports that proceed a drive failure should list the
drive identification beyond just the /dev/sdX kind of thing, which is
subject to change if you add more SAS devices.

I once researched what it would take to implement the drive failure lights
on the typical brand name server/storage chassis, there's a command for
manipulating SES devices such as those lights, the catch is figuring out
the mapping between the drives and lights, its not always evident, so would
require trial and error.

On Wed, Nov 11, 2020 at 5:37 PM Valeri Galtsev <galtsev at kicp.uchicago.edu>

> > On Nov 11, 2020, at 6:00 PM, John Pierce <jhn.pierce at gmail.com> wrote:
> >
> > On Wed, Nov 11, 2020 at 3:38 PM Warren Young <warren at etr-usa.com> wrote:
> >
> >> On Nov 11, 2020, at 2:01 PM, hw <hw at gc-24.de> wrote:
> >>>
> >>> I have yet to see software RAID that doesn't kill the performance.
> >>
> >> When was the last time you tried it?
> >>
> >> Why would you expect that a modern 8-core Intel CPU would impede I/O in
> >> any measureable way as compared to the outdated single-core 32-bit RISC
> >> typically found on hardware RAID cards?  These are the same CPUs, mind,
> >> that regularly crunch through TLS 1.3 on line-rate fiber Ethernet
> links, a
> >> much tougher task than mediating spinning disk I/O.
> >
> >
> > the only 'advantage' hardware raid has is write-back caching.
> Just for my information: how do you map failed software RAID drive to
> physical port of, say, SAS-attached enclosure. I’d love to hot replace
> failed drives in software RAIDs, have over hundred physical drives attached
> to a machine. Do not criticize, this is box installed by someone else, I
> have “inherited” it.To replace I have to query drive serial number, power
> off the machine and pulling drives one at a time read the labels...
> With hardware RAID that is not an issue, I always know which physical port
> failed drive is in. And I can tell controller to “indicate” specific drive
> (it blinks respective port LED). Always hot replacing drives in hardware
> RAIDs, no one ever knows it has been done. And I’d love to deal same way
> with drives in software RAIDs.
> Thanks for advises in advance. And my apologies for “stealing the thread"
> Valeri
> > with ZFS you can get much the same performance boost out of a small fast
> > SSD used as a ZIL / SLOG.
> >
> > --
> > -john r pierce
> >  recycling used bits in santa cruz
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-john r pierce
  recycling used bits in santa cruz