[SOLVED] Enable persistent reservations for iSCSI volumes

stivraboti · 11-20-2019, 06:31 AM

Hi,

I have configured iSCSI LUNs (targets) on Deiban 9 using targetcli-fb. Everything is working as expected. The problem comes when I try to use the LUNs as cluster storage for Xen or MS SQL - they require persistent reservations. I have installed sg3-utils to try to use sg_persist to turn on persistence for my targets/volumes but without any luck (I am really new to the iSCSI scene). I wen thru the man page for sg_persist, but I am struggling understanding its concept.

My LUNs are using FILEIO images and the images are located in /mystorage.
Here is what I've tried so far:

Code:

root@[REDACTED]~# sg_persist --in --report-capabilities -v /dev/vdb
    inquiry cdb: 12 00 00 00 24 00
inquiry: scsi status: Unknown status [0x7e]
sg_persist: /dev/vdb doesn't respond to a SCSI INQUIRY

Code:

root@[REDACTED] ~# sg_persist --in --report-capabilities -v /storage
    inquiry cdb: 12 00 00 00 24 00
inquiry: pass through os error: Inappropriate ioctl for device
sg_persist: /storage doesn't respond to a SCSI INQUIRY

Code:

root@[REDACTED] ~# sg_persist --device=/dev/vdb
>> No service action given; assume Persistent Reserve In command
>> with Read Keys service action
inquiry: scsi status: Unknown status [0x7e]
sg_persist: /dev/vdb doesn't respond to a SCSI INQUIRY

Code:

root@[REDACTED] ~# sg_persist --out --register --param-sark=123test /dev/vdb
inquiry: scsi status: Unknown status [0x7e]
sg_persist: /dev/vdb doesn't respond to a SCSI INQUIRY

Code:

root@[REDACTED] ~# sg_persist --out --register --param-sark=123test /storage/vol01.img
inquiry: pass through os error: Inappropriate ioctl for device
sg_persist: /storage/vol01.img doesn't respond to a SCSI INQUIRY

Here are more details:
- My /storage folder is located on: /dev/vdb/storage (LVM)
- System: Linux [REDACTED] 4.9.0-8-amd64 #1 SMP Debian 4.9.110-3+deb9u4 (2018-08-21) x86_64 GNU/Linux
- Targetcli version: targetcli version 2.1.fb43
- My initiators are on Windows Server 2019 (SQL 2017)

Code:

root@[REDACTED] ~# cat /sys/kernel/config/target/core/fileio_0/[REDACTED]/pr/res_*
APTPL Bit Status: Disabled
Ready to process PR APTPL metadata..
No SPC-3 Reservation holder
No SPC-3 Reservation holder
0x0000002d
No SPC-3 Reservation holder
SPC-3 PR Registrations:
iSCSI Node: iqn.[REDACTED],i,0x400001370000 Key: [REDACTED] PRgen: 0x0000002c
No SPC-3 Reservation holder
SPC3_PERSISTENT_RESERVATIONS

Some general guidance will mean a lot!

smallpond · 11-20-2019, 05:14 PM

Testing PR using sg_persist needs to be done from the client, not on the target. It is implemented in the target code, so is only available over the network. See file drivers/target/target_core_pr.c.

Example calls can be found here: http://www.linux-iscsi.org/wiki/Persistent_Reservations

stivraboti · 11-21-2019, 03:04 AM

EDIT: Duplicated answer.

stivraboti · 11-21-2019, 03:14 AM

Quote:

Originally Posted by smallpond

Testing PR using sg_persist needs to be done from the client, not on the target. It is implemented in the target code, so is only available over the network. See file drivers/target/target_core_pr.c.

Example calls can be found here: http://www.linux-iscsi.org/wiki/Persistent_Reservations

Thank you for your reply.
If the persistence mode has to be triggered from the client, don't I have to configure APTPL Bit Status: Disabled from the server/target to Enabled? I have researched it, but not sure how to do it.

smallpond · 11-24-2019, 04:57 PM

Why do you need to enable that? Are your servers not on UPS?

stivraboti · 11-25-2019, 07:52 AM

Quote:

Originally Posted by smallpond

Why do you need to enable that? Are your servers not on UPS?

When I run MS cluster validation report it says that persistent reservation is not enabled.

smallpond · 11-25-2019, 10:38 AM

There is no enable. Byte 2 of the inquiry data gives the SCSI version that is supported.

Code:

03 - SPC    SCSI-2 reservations
04 - SPC-2  basic PR
05 - SPC-3  multi-initiator PR

stivraboti · 11-26-2019, 03:17 AM

Quote:

Originally Posted by smallpond

There is no enable. Byte 2 of the inquiry data gives the SCSI version that is supported.

Code:

03 - SPC    SCSI-2 reservations
04 - SPC-2  basic PR
05 - SPC-3  multi-initiator PR

Thank you for the clarification.
I managed to bypass the validation by creating the /var/target/pr folder manually. Everything is okay now.