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From: Ming Zhang <blackmagic02881@gmail.com>
To: Tomasz Chmielewski <mangoo@wpkg.org>
Cc: FUJITA Tomonori <tomof@acm.org>,
	vst@vlnb.net, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	James.Bottomley@HansenPartnership.com,
	scst-devel@lists.sourceforge.net, stgt-devel@lists.berlios.de,
	akpm@linux-foundation.org, torvalds@linux-foundation.org,
	fujita.tomonori@lab.ntt.co.jp
Subject: Re: [Scst-devel] Integration of SCST in the mainstream Linux kernel
Date: Tue, 05 Feb 2008 11:21:47 -0500	[thread overview]
Message-ID: <1202228507.4096.11.camel@dhcp-117.ibrix.com> (raw)
In-Reply-To: <47A889AB.9090301@wpkg.org>

On Tue, 2008-02-05 at 17:07 +0100, Tomasz Chmielewski wrote:
> FUJITA Tomonori schrieb:
> > On Tue, 05 Feb 2008 08:14:01 +0100
> > Tomasz Chmielewski <mangoo@wpkg.org> wrote:
> > 
> >> James Bottomley schrieb:
> >>
> >>> These are both features being independently worked on, are they not?
> >>> Even if they weren't, the combination of the size of SCST in kernel plus
> >>> the problem of having to find a migration path for the current STGT
> >>> users still looks to me to involve the greater amount of work.
> >> I don't want to be mean, but does anyone actually use STGT in
> >> production? Seriously?
> >>
> >> In the latest development version of STGT, it's only possible to stop
> >> the tgtd target daemon using KILL / 9 signal - which also means all
> >> iSCSI initiator connections are corrupted when tgtd target daemon is
> >> started again (kernel upgrade, target daemon upgrade, server reboot etc.).
> > 
> > I don't know what "iSCSI initiator connections are corrupted"
> > mean. But if you reboot a server, how can an iSCSI target
> > implementation keep iSCSI tcp connections?
> 
> The problem with tgtd is that you can't start it (configured) in an
> "atomic" way.
> Usually, one will start tgtd and it's configuration in a script (I 
> replaced some parameters with "..." to make it shorter and more readable):
> 
> 
> tgtd
> tgtadm --op new ...
> tgtadm --lld iscsi --op new ...
> 
> 
> However, this won't work - tgtd goes immediately in the background as it 
> is still starting, and the first tgtadm commands will fail:

this should be a easy fix. start tgtd, get port setup ready in forked
process, then signal its parent that ready to quit. or set port ready in
parent, fork and pass to daemon.


> 
> # bash -x tgtd-start
> + tgtd
> + tgtadm --op new --mode target ...
> tgtadm: can't connect to the tgt daemon, Connection refused
> tgtadm: can't send the request to the tgt daemon, Transport endpoint is 
> not connected
> + tgtadm --lld iscsi --op new --mode account ...
> tgtadm: can't connect to the tgt daemon, Connection refused
> tgtadm: can't send the request to the tgt daemon, Transport endpoint is 
> not connected
> + tgtadm --lld iscsi --op bind --mode account --tid 1 ...
> tgtadm: can't find the target
> + tgtadm --op new --mode logicalunit --tid 1 --lun 1 ...
> tgtadm: can't find the target
> + tgtadm --op bind --mode target --tid 1 -I ALL
> tgtadm: can't find the target
> + tgtadm --op new --mode target --tid 2 ...
> + tgtadm --op new --mode logicalunit --tid 2 --lun 1 ...
> + tgtadm --op bind --mode target --tid 2 -I ALL
> 
> 
> OK, if tgtd takes longer to start, perhaps it's a good idea to sleep a 
> second right after tgtd?
> 
> tgtd
> sleep 1
> tgtadm --op new ...
> tgtadm --lld iscsi --op new ...
> 
> 
> No, it is not a good idea - if tgtd listens on port 3260 *and* is 
> unconfigured yet,  any reconnecting initiator will fail, like below:

this is another easy fix. tgtd started with unconfigured status and then
a tgtadm can configure it and turn it into ready status.


those are really minor usability issue. ( i know it is painful for user,
i agree)


the major problem here is to discuss in architectural wise, which one is
better... linux kernel should have one implementation that is good from
foundation...





> 
> end_request: I/O error, dev sdb, sector 7045192
> Buffer I/O error on device sdb, logical block 880649
> lost page write due to I/O error on sdb
> Aborting journal on device sdb.
> ext3_abort called.
> EXT3-fs error (device sdb): ext3_journal_start_sb: Detected aborted journal
> Remounting filesystem read-only
> end_request: I/O error, dev sdb, sector 7045880
> Buffer I/O error on device sdb, logical block 880735
> lost page write due to I/O error on sdb
> end_request: I/O error, dev sdb, sector 6728
> Buffer I/O error on device sdb, logical block 841
> lost page write due to I/O error on sdb
> end_request: I/O error, dev sdb, sector 7045192
> Buffer I/O error on device sdb, logical block 880649
> lost page write due to I/O error on sdb
> end_request: I/O error, dev sdb, sector 7045880
> Buffer I/O error on device sdb, logical block 880735
> lost page write due to I/O error on sdb
> __journal_remove_journal_head: freeing b_frozen_data
> __journal_remove_journal_head: freeing b_frozen_data
> 
> 
> Ouch.
> 
> So the only way to start/restart tgtd reliably is to do hacks which are 
> needed with yet another iSCSI kernel implementation (IET): use iptables.
> 
> iptables <block iSCSI traffic>
> tgtd
> sleep 1
> tgtadm --op new ...
> tgtadm --lld iscsi --op new ...
> iptables <unblock iSCSI traffic>
> 
> 
> A bit ugly, isn't it?
> Having to tinker with a firewall in order to start a daemon is by no 
> means a sign of a well-tested and mature project.
> 
> That's why I asked how many people use stgt in a production environment 
> - James was worried about a potential migration path for current users.
> 
> 
> 
> -- 
> Tomasz Chmielewski
> http://wpkg.org
> 
> 
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-- 
Ming Zhang


@#$%^ purging memory... (*!%
http://blackmagic02881.wordpress.com/
http://www.linkedin.com/in/blackmagic02881
--------------------------------------------


  reply	other threads:[~2008-02-05 16:22 UTC|newest]

Thread overview: 148+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-23 14:22 Bart Van Assche
2008-01-23 17:11 ` Vladislav Bolkhovitin
2008-01-29 20:42 ` James Bottomley
2008-01-29 21:31   ` Roland Dreier
2008-01-29 23:32     ` FUJITA Tomonori
2008-01-30  1:15       ` [Scst-devel] " Vu Pham
2008-01-30  8:38       ` Bart Van Assche
2008-01-30 10:56         ` FUJITA Tomonori
2008-01-30 11:40           ` Vladislav Bolkhovitin
2008-01-30 13:10           ` Bart Van Assche
2008-01-30 13:54             ` FUJITA Tomonori
2008-01-31  7:48               ` Bart Van Assche
2008-01-31 13:25           ` Nicholas A. Bellinger
2008-01-31 14:34             ` Bart Van Assche
2008-01-31 14:44               ` Nicholas A. Bellinger
2008-01-31 15:50               ` Vladislav Bolkhovitin
2008-01-31 16:25                 ` [Scst-devel] " Joe Landman
2008-01-31 17:08                   ` Bart Van Assche
2008-01-31 17:13                     ` Joe Landman
2008-01-31 18:12                     ` David Dillow
2008-02-01 11:50                       ` Vladislav Bolkhovitin
2008-02-01 11:50                     ` Vladislav Bolkhovitin
2008-02-01 12:25                       ` Vladislav Bolkhovitin
2008-01-31 17:14                 ` Nicholas A. Bellinger
2008-01-31 17:40                   ` Bart Van Assche
2008-01-31 18:15                     ` Nicholas A. Bellinger
2008-02-01  9:08                       ` Bart Van Assche
2008-02-01  8:11             ` Bart Van Assche
2008-02-01 10:39               ` Nicholas A. Bellinger
2008-02-01 11:04                 ` Bart Van Assche
2008-02-01 12:05                   ` Nicholas A. Bellinger
2008-02-01 13:25                     ` Bart Van Assche
2008-02-01 14:36                       ` Nicholas A. Bellinger
2008-01-30 16:34         ` James Bottomley
2008-01-30 16:50           ` Bart Van Assche
2008-02-02 15:32           ` Pete Wyckoff
2008-02-05 17:01         ` Erez Zilber
2008-02-06 12:16           ` Bart Van Assche
2008-02-06 16:45             ` Benny Halevy
2008-02-06 17:06             ` Roland Dreier
2008-02-18  9:43             ` Erez Zilber
2008-02-18 11:01               ` Bart Van Assche
2008-02-20  7:34                 ` Erez Zilber
2008-02-20  8:41                   ` Bart Van Assche
2008-01-30 11:18       ` Vladislav Bolkhovitin
2008-01-30  8:29   ` Bart Van Assche
2008-01-30 16:22     ` James Bottomley
2008-01-30 17:03       ` Bart Van Assche
2008-02-05  7:14       ` [Scst-devel] " Tomasz Chmielewski
2008-02-05 13:38         ` FUJITA Tomonori
2008-02-05 16:07           ` Tomasz Chmielewski
2008-02-05 16:21             ` Ming Zhang [this message]
2008-02-05 16:43             ` FUJITA Tomonori
2008-02-05 17:09           ` Matteo Tescione
2008-02-06  1:29             ` FUJITA Tomonori
2008-02-06  2:01               ` Nicholas A. Bellinger
2008-01-30 11:17   ` Vladislav Bolkhovitin
2008-02-04 12:27     ` Vladislav Bolkhovitin
2008-02-04 13:53       ` Bart Van Assche
2008-02-04 17:00         ` David Dillow
2008-02-04 17:08         ` Vladislav Bolkhovitin
2008-02-05 16:25         ` Bart Van Assche
2008-02-05 18:18           ` Linus Torvalds
2008-02-04 15:30       ` James Bottomley
2008-02-04 16:25         ` Vladislav Bolkhovitin
2008-02-04 17:06           ` James Bottomley
2008-02-04 17:16             ` Vladislav Bolkhovitin
2008-02-04 17:25               ` James Bottomley
2008-02-04 17:56                 ` Vladislav Bolkhovitin
2008-02-04 18:22                   ` James Bottomley
2008-02-04 18:38                     ` Vladislav Bolkhovitin
2008-02-04 18:54                       ` James Bottomley
2008-02-05 18:59                         ` Vladislav Bolkhovitin
2008-02-05 19:13                           ` James Bottomley
2008-02-06 18:07                             ` Vladislav Bolkhovitin
2008-02-07 13:13                             ` [Scst-devel] " Bart Van Assche
2008-02-07 13:45                               ` Vladislav Bolkhovitin
2008-02-07 22:51                                 ` david
2008-02-08 10:37                                   ` Vladislav Bolkhovitin
2008-02-09  7:40                                     ` david
2008-02-08 11:33                                   ` Nicholas A. Bellinger
2008-02-08 14:36                                     ` Vladislav Bolkhovitin
2008-02-08 23:53                                       ` Nicholas A. Bellinger
2008-02-15 15:02                                 ` Bart Van Assche
2008-02-07 15:38                               ` [Scst-devel] " Nicholas A. Bellinger
2008-02-07 20:37                                 ` Luben Tuikov
2008-02-08 10:32                                   ` Vladislav Bolkhovitin
2008-02-09  7:32                                     ` Luben Tuikov
2008-02-11 10:02                                       ` Vladislav Bolkhovitin
2008-02-08 11:53                                   ` [Scst-devel] " Nicholas A. Bellinger
2008-02-08 14:42                                     ` Vladislav Bolkhovitin
2008-02-09  0:00                                       ` Nicholas A. Bellinger
2008-02-04 18:29                 ` Linus Torvalds
2008-02-04 18:49                   ` James Bottomley
2008-02-04 19:06                   ` Nicholas A. Bellinger
2008-02-04 19:19                     ` Nicholas A. Bellinger
2008-02-04 19:44                     ` Linus Torvalds
2008-02-04 20:06                       ` [Scst-devel] " 4news
2008-02-04 20:24                       ` Nicholas A. Bellinger
2008-02-04 21:01                       ` J. Bruce Fields
2008-02-04 21:24                         ` Linus Torvalds
2008-02-04 22:00                           ` Nicholas A. Bellinger
2008-02-04 22:57                           ` Jeff Garzik
2008-02-04 23:45                             ` Linus Torvalds
2008-02-05  0:08                               ` Jeff Garzik
2008-02-05  1:20                                 ` Linus Torvalds
2008-02-05  8:38                             ` Bart Van Assche
2008-02-05 17:50                               ` Jeff Garzik
2008-02-06 10:22                                 ` Bart Van Assche
2008-02-06 14:21                                   ` Jeff Garzik
2008-02-05 13:05                             ` Olivier Galibert
2008-02-05 18:08                               ` Jeff Garzik
2008-02-05 19:01                           ` Vladislav Bolkhovitin
2008-02-04 22:43                       ` Alan Cox
2008-02-04 17:30                         ` Douglas Gilbert
2008-02-05  2:07                           ` [Scst-devel] " Chris Weiss
2008-02-05 14:19                             ` FUJITA Tomonori
2008-02-04 22:59                         ` Nicholas A. Bellinger
2008-02-04 23:00                         ` James Bottomley
2008-02-04 23:12                           ` Nicholas A. Bellinger
2008-02-04 23:16                             ` Nicholas A. Bellinger
2008-02-05 18:37                             ` James Bottomley
2008-02-04 23:04                         ` Jeff Garzik
2008-02-04 23:27                           ` Linus Torvalds
2008-02-05 19:01                           ` Vladislav Bolkhovitin
2008-02-05 19:12                             ` Jeff Garzik
2008-02-05 19:21                               ` Vladislav Bolkhovitin
2008-02-06  0:11                                 ` Nicholas A. Bellinger
2008-02-06  1:43                                   ` Nicholas A. Bellinger
2008-02-12 16:05                                   ` [Scst-devel] " Bart Van Assche
2008-02-13  3:44                                     ` Nicholas A. Bellinger
2008-02-13  6:18                                       ` CONFIG_SLUB and reproducable general protection faults on 2.6.2x Nicholas A. Bellinger
2008-02-13 16:37                                         ` Nicholas A. Bellinger
2008-02-06  0:17                               ` Integration of SCST in the mainstream Linux kernel Nicholas A. Bellinger
2008-02-06  0:48                             ` Nicholas A. Bellinger
2008-02-06  0:51                               ` Nicholas A. Bellinger
2008-02-05  0:07                         ` Matt Mackall
2008-02-05  0:24                           ` Linus Torvalds
2008-02-05  0:42                             ` Jeff Garzik
2008-02-05  0:45                             ` Matt Mackall
2008-02-05  4:43                             ` [Scst-devel] " Matteo Tescione
2008-02-05  5:07                               ` James Bottomley
2008-02-05 13:38                               ` FUJITA Tomonori
2008-02-05 19:00                       ` Vladislav Bolkhovitin
2008-02-05 17:10 ` Erez Zilber
2008-02-05 19:02   ` Bart Van Assche
2008-02-05 19:02   ` Vladislav Bolkhovitin
2008-02-09  7:44 [Scst-devel] " Luben Tuikov

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