On 09/25/15 at 06:03pm, Minfei Huang wrote:
On 09/25/15 at 02:39pm, Dave Young wrote:
> On 09/24/15 at 01:29pm, Minfei Huang wrote:
> > Hardware iscsi can export the iscsi device before starting to load the
> > kernel code, which setups the iscsi card using the config stored in
> > hardward iscsi card memory.
> >
> > kdump need not do anything for this sort of hardware iscsi card, if this
> > card does not have the feature iBFT. IBFT can export the iscsi
> > configuration from hardware iscsi card memroy to current running kernel.
> > Thus iscsiadm cann't get the iscsi session info using "iscsiadm -m
> > session -r /sys/block/xxx", due to limitation of iscsi info exported by
> > kernel.
> >
> > Once the machine is plugged in this sort of hardware iscsi card, kdump
> > returns as soon as possible.
>
> Since we do not know much about iscsi, could you describe the basic infomation
> about them?
>
> 1. how many type of cases we should consider for iscsi?
There are three iscsi initiators we use more frequently.
1) software iscsi initiator
2) iSCSI HBA
3) iBFT
>
> 2. what is the difference between them, how to diffrentiate them.
1) software iscsi initiator
- We can setup the iscsi environemnt by using tgt suit. It is more
continent to setup the iscsi without the hardware supporting.
2) iSCSI HBA
- System has no ability to detect the iscsi session config. The
usage of exported iSCSI device is the same as local SCSI device.
3) iBFT
- The iSCSI Bios Firmware Table (iBFT) is a table that is created in
memory which is mapped with the iSCSI card firmware. Thus we can get
the session config according to the command iscsiadm.
>
> 3. how to setup them (basic steps)
1) software iscsi initiator
- According to the command iscsiadm to setup the available seesion,
and the session info should be passed manually
2) iSCSI HBA
- Do nothing, except for passing "rd.iscsi.firmware=1" to the
kernel. The iSCSI device will use the config stored in firmware to
setup the session.
So assume your patch is for addressing 2), if it is a boot disk there should
be rd.iscsi.firmware=1 in /proc/cmdline, but if it is not a boot disk, we need
pass this param to second kernel?
What if there's both 2) and 1) existed?
3) iBFT
- Pass "rd.iscsi.ibft=1" and "rd.iscsi.firmware=1" to the kernel
to
setup the session.
Thanks
Minfei
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