From 353d1f1928adf9546f2345126f2843aedc559450 Mon Sep 17 00:00:00 2001 From: Vladislav Bolkhovitin Date: Fri, 27 May 2016 01:02:11 +0000 Subject: [PATCH] scst: update README how to configure SCST, so VMware start using EXTENDED COPY between datastores Based on information from Artur Piechocki Tested-By: Isaac Goldbaum git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@6892 d57e44dd-8a1f-0410-8b47-8ef2f437770f --- scst/README | 28 ++++++++++++++++++++++++++++ scst/README_in-tree | 28 ++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+) diff --git a/scst/README b/scst/README index c15c718f2..9f4aac4ac 100644 --- a/scst/README +++ b/scst/README @@ -1827,6 +1827,34 @@ benefit from SCST VAAI implementation. Those actions described in the implementation notes below. For vdisk and fileio_tgt handlers they have already been implemented. +IMPORTANT: To use EXTENDED COPY command between LUNs (datastores) they all +========= MUST have the same PRODUCT IDENTIFICATION INQUIRY field. By + default, to simplify remote devices identification, SCST uses + vdisk names as PRODUCT IDENTIFICATION, so SCST devices look + differently from the initiators. However, for some reasons, + VMware does not use EXTENDED COPY between LUNs with different + PRODUCT IDENTIFICATION. Thus, to be able to use full VAAI in + your VMware setups you must manually set PRODUCT + IDENTIFICATION for all your VMware LUNs to the same value, + for instance, "SCST", via using "prod_id" attribute. It could + be done either by adding "prod_id" attribute to scstadmin + scst.conf, or by directly writing to SCST sysfs attribute. + For example: + + HANDLER vdisk_blockio { + DEVICE blockio1 { + filename /dev/sda5 + prod_id SCST + } + + or + + echo SCST >/sys/kernel/scst_tgt/devices/blockio1/prod_id + correspondingly. + + Note, this prod_id modification must be done on all + datastores BEFORE VMware connects to them. + Implementation notes .................... diff --git a/scst/README_in-tree b/scst/README_in-tree index 0bdc68618..78e94401d 100644 --- a/scst/README_in-tree +++ b/scst/README_in-tree @@ -1680,6 +1680,34 @@ benefit from SCST VAAI implementation. Those actions described in the implementation notes below. For vdisk and fileio_tgt handlers they have already been implemented. +IMPORTANT: To use EXTENDED COPY command between LUNs (datastores) they all +========= MUST have the same PRODUCT IDENTIFICATION INQUIRY field. By + default, to simplify remote devices identification, SCST uses + vdisk names as PRODUCT IDENTIFICATION, so SCST devices look + differently from the initiators. However, for some reasons, + VMware does not use EXTENDED COPY between LUNs with different + PRODUCT IDENTIFICATION. Thus, to be able to use full VAAI in + your VMware setups you must manually set PRODUCT + IDENTIFICATION for all your VMware LUNs to the same value, + for instance, "SCST", via using "prod_id" attribute. It could + be done either by adding "prod_id" attribute to scstadmin + scst.conf, or by directly writing to SCST sysfs attribute. + For example: + + HANDLER vdisk_blockio { + DEVICE blockio1 { + filename /dev/sda5 + prod_id SCST + } + + or + + echo SCST >/sys/kernel/scst_tgt/devices/blockio1/prod_id + correspondingly. + + Note, this prod_id modification must be done on all + datastores BEFORE VMware connects to them. + Implementation notes ....................