I am sponsoring this fasttrack for Jim Dunham. Timeout is set for 01/13/2010.
- John
Template Version: @(#)sac_nextcase 1.68 02/23/09 SMI
This information is Copyright 2010 Sun Microsystems
1. Introduction
1.1. Project/Component Working Name:
EOF of iSCSI Target Daemon
1.2. Name of Document Author/Supplier:
Author: James Dunham
1.3 Date of This Document:
06 January, 2010
2. Project Summary
2.1. Project Description
This proposal is to remove support for the iSCSI Target Daemon
from Solaris Next and OpenSolaris. This fast-track is for advance
warning that within Solaris Next and OpenSolaris, the iSCSI Target
Daemon, the CLI iscsitadm, the man page iscsitadm(1M), and ZFS's
support for 'shareiscsi' support for ZVOLs will be removed.
The PSARC cases being deprecated as a result of accepting this proposal
are as follows:
- PSARC/2007/153 iSCSI target provider
- PSARC/2007/414 SCF changes for iSCSI Target
- PSARC/2006/622 iSCSI/ZFS Integration
- PSARC/2009/168 iSCSI Target PGR directory for ZVOLs
The iSCSI Target in COMSTAR will replace all of the aforementioned
functionality in Solaris Next and OpenSolaris, with the exception of
ZFS's support for 'shareiscsi'.
COMSTAR consists of the following PSARC cases:
- PSARC/2007/523 COMSTAR: Common Multiprotocol SCSI Target
- PSARC/2008/235 SCSI Block Disk Provider for COMSTAR
- PSARC/2008/587 iSCSI Port Provider for COMSTAR
- PSARC/2009/111 COMSTAR Infiniband SRP Target
- PSARC/2008/395 iSER: iSCSI Extensions for RDMA
- PSARC/2008/310 FCoE (Fibre Channel over Ethernet) Target
2.2. Risks and Assumptions
The architectural design of the iSCSI Target Daemon and ZFS's shareiscsi
support, being PSARC/2006/662, is not extensible in its present form, as
the underlying implementation is based on a tight association many iSCSI
Targets, supporting only a LUN 0, for each shareiscsi enabled ZVOL.
COMSTAR's is a multi-protocol SCSI Target implementation that provides
support for different types of SCSI Targets, not just iSCSI, supporting
LUN numbers up to 16K. ZVOLs are used as backing store devices for SCSI
Initiators using one or more or COMSTAR's support protocols.
Although the iSCSI Target in COMSTAR is a functional replacement for the
iSCSI Target Daemon, there is no means to provide an automated upgrade
from one form of iSCSI Target to the other. The iSCSI Target Daemon, and
ZFS shareiscsi support, presented a model of many iSCSI Target IDs, with
one iSCSI LUNs per target. The iSCSI Target in COMSTAR presents a model
of limited iSCSI Target IDs, currently 32, and many iSCSI LUNs per
target, up to 16384. A many targets and one LU model, does not map
into a few targets, with many LU model.
As part of the Solaris Next documentation, a step by step description
of how to upgrade existing iSCSI Target Daemon LUs to iSCSI Target LUs
in COMSTAR will be provided.
3. Business Summary
3.1. Problem Area
Providing and supporting two different implementations of an iSCSI
Target service is confusing to both system administrators and end users
of Solaris, and also creates an unwanted support burden on Sun, having
to support two totally different implementations of an iSCSI Target.
The iSCSI Target in COMSTAR, and its use in the Sun Storage 7000 Unified
Storage Server, the iSCSI Target in COMSTAR has proven itself as an
enterprise class iSCSI Target implementation, in features,
functionality, performance and overall stability. This is not the
general consensus with the iSCSI Target Daemon, known to be an inferior
iSCSI Target implementation.
3.2. Market/Requester
3.3. Business Justification
The iSCSI Target in COMSTAR is built on an enterprise class, Common
Multiprotocol SCSI Target, that in addition to providing support for
iSCSI Targets, it also provides support for iSER, SRP, FC and FCoE SCSI
Targets.
COMSTAR provides proven block based SCSI Targets support for Solaris
Next, OpenSolaris and the Sun Storage 7000 Unified Storage Systems.
3.4. Competitive Analysis
Sun has a unique position over other storage vendors and operating
systems, in that the iSCSI Target in COMSTAR is Open Source, based on
Open Standards, for ubiquitous access to Open Storage.
3.5. Opportunity Window/Exposure
Solaris Next, OpenSolaris, Sun Storage 7000 Unified Storage Systems
3.6. How will you know when you are done?
Removal of the iSCSI Target in Solaris Next, OpenSolaris, and an
installed based that is using the iSCSI Target in COMSTAR, as a
replacement for the iSCSI Target Daemon.
4. Technical Description
The iSCSI Target Daemon is an inferior implementation when compared to
the iSCSI Target in COMSTAR. The iSCSI Target Daemon, supports only a
single SCSI Target implementation, has been noted by storage-discuss,
RPE and within the Sun Storage 7000 Unified Storage Server as being
underperforming, with known scalability issues when used with Solaris,
and other operating systems supporting iSCSI Initiators.
A point worth stating is that an iSCSI Target listens for iSCSI
Initiator requests on TCP/IP port 3260. This means that two different
implementations of iSCSI Target can not run at the same time, on
the same Solaris host.
Therefore, when iSCSI Target in COMSTAR is active on a Solaris host,
ZFS's shareiscsi support no longer works, even though the iSCSI Target
Daemon has yet to be removed.
All of these issues and more, were eliminated with the design,
development and successful release of the iSCSI Target in COMSTAR.
6. Resources and Schedule
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: FastTrack
6.6. ARC Exposure: open
