From: "Martin K. Petersen" <martin.petersen-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
To: Tom Yan <tom.ty89-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: "Martin K. Petersen"
<martin.petersen-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>,
linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Karel Zak <kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
util-linux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: optimal io size / custom alignment
Date: Thu, 18 Jun 2015 17:01:19 -0400 [thread overview]
Message-ID: <yq1a8vwenog.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <CAGnHSEnMgivXU_0gDaOkHFkbc=Ve8PaPR0ho8+VhdcUuNu89Gw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> (Tom Yan's message of "Wed, 17 Jun 2015 17:49:51 +0800")
>>>>> "Tom" == Tom Yan <tom.ty89-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:
Tom> No I put it in the wrong way. What I meant was "sd vs md". For
Tom> example, couldn't the scsi disk driver bind the value it reads from
Tom> the VPD to another variable instead of "optimal i/o size", so that
Tom> this value would be exclusively for RAID (and other virtual
Tom> devices)?
Who says that RAID is a virtual device? Hardware RAID controllers as
well as SAS, iSCSI and Fibre Channel disk arrays all use the Block
Limits VPD to communicate their preferred I/O size and alignment to
us. As do enterprise disk drives.
We deal with broken devices by blacklisting them. I suggest you try to
find a way we can reliably identify your UAS devices. If there is a
common pattern, we can entertain adding a workaround.
--
Martin K. Petersen Oracle Linux Engineering
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WARNING: multiple messages have this Message-ID (diff)
From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Tom Yan <tom.ty89@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org, Karel Zak <kzak@redhat.com>,
util-linux@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: optimal io size / custom alignment
Date: Thu, 18 Jun 2015 17:01:19 -0400 [thread overview]
Message-ID: <yq1a8vwenog.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <CAGnHSEnMgivXU_0gDaOkHFkbc=Ve8PaPR0ho8+VhdcUuNu89Gw@mail.gmail.com> (Tom Yan's message of "Wed, 17 Jun 2015 17:49:51 +0800")
>>>>> "Tom" == Tom Yan <tom.ty89@gmail.com> writes:
Tom> No I put it in the wrong way. What I meant was "sd vs md". For
Tom> example, couldn't the scsi disk driver bind the value it reads from
Tom> the VPD to another variable instead of "optimal i/o size", so that
Tom> this value would be exclusively for RAID (and other virtual
Tom> devices)?
Who says that RAID is a virtual device? Hardware RAID controllers as
well as SAS, iSCSI and Fibre Channel disk arrays all use the Block
Limits VPD to communicate their preferred I/O size and alignment to
us. As do enterprise disk drives.
We deal with broken devices by blacklisting them. I suggest you try to
find a way we can reliably identify your UAS devices. If there is a
common pattern, we can entertain adding a workaround.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2015-06-18 21:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-13 14:52 optimal io size / custom alignment Tom Yan
2015-06-15 13:31 ` Karel Zak
2015-06-16 5:20 ` Tom Yan
2015-06-16 5:37 ` Tom Yan
2015-06-16 9:43 ` Karel Zak
[not found] ` <20150616094320.GX1992-xkT7n84Rsxv/9pzu0YdTqQ@public.gmane.org>
2015-06-16 10:22 ` Tom Yan
2015-06-16 10:22 ` Tom Yan
2015-06-16 17:08 ` Martin K. Petersen
[not found] ` <yq1zj3zfuna.fsf-+q57XtR/GgMb6DWv4sQWN6xOck334EZe@public.gmane.org>
2015-06-16 19:26 ` Tom Yan
2015-06-16 19:26 ` Tom Yan
2015-06-16 21:28 ` Martin K. Petersen
[not found] ` <yq1d20vfimj.fsf-+q57XtR/GgMb6DWv4sQWN6xOck334EZe@public.gmane.org>
2015-06-17 9:49 ` Tom Yan
2015-06-17 9:49 ` Tom Yan
[not found] ` <CAGnHSEnMgivXU_0gDaOkHFkbc=Ve8PaPR0ho8+VhdcUuNu89Gw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-06-18 21:01 ` Martin K. Petersen [this message]
2015-06-18 21:01 ` Martin K. Petersen
[not found] ` <yq1a8vwenog.fsf-+q57XtR/GgMb6DWv4sQWN6xOck334EZe@public.gmane.org>
2015-06-20 16:01 ` Tom Yan
2015-06-20 16:01 ` Tom Yan
[not found] ` <CAGnHSE=DGa24TPox8wp4k264jnXjMOq7kzf-tCRf1eJt9kN0ZQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-06-21 0:12 ` Martin K. Petersen
2015-06-21 0:12 ` Martin K. Petersen
2015-06-22 14:32 ` Alan Stern
2015-06-22 14:32 ` Alan Stern
2015-07-12 4:19 ` optimal io size / custom alignment -- caution on custom aligns Linda Walsh
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