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Questions[jbod](server)

Martin Hope
Binarus
Asked: 2020-12-30 15:10:30 +0800 CST
  • 1

I am currently trying to configure an LSI SAS 12G HBA with the 3108 chip (it is a 9361-8i, but I am nearly sure that my question relates to similar HBAs as well).

I have understood the differences between the JBOD and the RAID personalities, but there is another related setting which I currently can't make sense of. This setting is called behavior mode and is only available when the controller is in JBOD personality.

In JBOD personality, the behavior mode can be set to JBOD or None. Could somebody please shortly explain what this is about?

I have studied the manual linked below, and several more from Broadcom's web site, and have tried hard to find an explanation elsewhere as well, but to no avail.

The manual is here: https://docs.broadcom.com/doc/pub-005110

What I am talking about is shown e.g.

  • In chapter 5.3.3 on page 111

"JBOD- The Behavior modes available under this mode are JBOD and None."

  • In the last row of table 29 on page 135

  • In the third-to-last row of table 42 on page 196

... and eventually a few more.

lsi jbod
Martin Hope
julianjm
Asked: 2020-02-19 05:06:13 +0800 CST
  • 3

I'm reinstalling a workstation (not a headless server) with an Intel RAID card with BBU and 4GB internal cache.

My current setup uses ZFS on a pair of mechanical disks and a partition on an SSD for the ZIL.

I want to keep using ZFS on 2 bigger disks, mainly because storage flexibility: filesystems and block devices. That comes handy for lxc containers, ability to make regular snapshots, etc.

The controller i'm about to use doesn't support write-caching on JBOD drives, but it does on 1 disk volumes with RAID0. That's the closest it gets to JBOD without loosing the battery backed write cache.

The main concern I have is the lack of SMART information available to ZFS. I can query the drives directly with smartctl -d megaraid,S /dev/sdb, being S the drive slot on the controller. I'm not sure if ZFS if capable of using that.

As I said, this is for a personal workstation. What do you think? Having thousands of fsyncs/s thanks to the write cache, do I need ZIL o can I live without it?

Any specific settings on the controller (regarding the SMART management) that I should take into account?

Thanks

zfs hardware-raid jbod raid0
Martin Hope
ausip
Asked: 2017-03-16 01:30:05 +0800 CST
  • 1

In the Exchange 2016 preferred architecture recommendations put out by Microsoft. The recommendation is for JBOD storage for information stores. I understand the basis of the recommendation and the semantics of recovery etc. but I am trying to get clarification on Microsoft's definition of JBOD.

In the RAID controller world, JBOD can be defined as a bunch of disks bundled together and displayed as one drive. ie: no RAID level, concatenated to make one large volume.

I am assuming that Microsoft's definition is displaying each individual disk to the OS as an individual volume.

Thoughts please...

Microsoft's - The Preferred Architecture

exchange jbod exchange-2016
Martin Hope
drookie
Asked: 2016-12-27 08:53:05 +0800 CST
  • 1

I have an LSI SAS9300-4i4e controller, plugged into a SuperServer 6018U-TRTP+ server and connected with mini-sasHD cable to a Supermicro SC216BE1C-R741JBOD chassis, which has several Toshiba SSD disks installed. The controller doesn't see any disks (it reports it in it's configuration utility, when OS is booted it doesn't see any diosks too). What is even worse, I have two pairs of such equipment, and both are installed on a remote site. I have IPMI connectivity with both servers and JBOD chassises, and I'm out of ideas what may be wrong. I'm also running the identical server + JBOD chassis in another datacenter, with same controler (same cable of course), and this installation is fully functional.

So far I can tell that:

  • JBOD chassis is powered up, disks are flashing with their LEDs (thusthey are receiving the power at least)
  • server is powered up for sure :)
  • the LSI controller runs the latest firmware (13.x) and the latest BIOS
  • the JBOD is connected to a proper server and the server has only one controller installed, holding only one external port, so there is no chance that I'm looking for disks on the wrong controller.

Am I right assuming that though JBOD chassis has an IPMI firmware too, this has nothing to do with the problem, thus it's upgrade (so far, however, I'm not seeing any IPMI firmware update for the JBOD) won't help ?

If anyone of you guys have any ideas on what to check, please feel free to describe it in the form of reply or in comments. I'm open to any decent ideas.

sas lsi supermicro jbod
Martin Hope
Phil Regnauld
Asked: 2016-12-03 15:10:06 +0800 CST
  • 6

I've got an LSI2208 integrated raid controller on a Supermicro X9DRH server board. It currently has a Logical Drive (LD) composed of 4 spinning disks. Now I want to add some more drives in JBOD, to let the OS access them directly (as opposed to creating a dedicated RAID0 LD per disk).

There are a couple of links (here for instance) explaining how to enable JBOD mode on LSI2208 controllers. This seems to be an all-or-nothing switch: either JBOD is supported on the controller, or not.

The command:

megacli -AdpSetProp EnableJBOD 1 -a0

... would enable JBOD mode on controller 0

From reading here, it seems that disks plugged into the controller but not associated with a Logical Disk become visible to the OS.

The question: is this a destructive operation? What happens to existing (RAID5/1/0) Logical Disk once this is done ? Or does this only affect disks not yet allocated to a Logical Disk ?

I could just try it out, but that means backing up several TB of data first.

Hope someone has an answer!

lsi jbod megacli