How to share storage device on logical block access level?

NTFSD
1

Hi,

Originally posted to ntdev list, maybe somebody here will be able to add
something to what guys in ntdev list wrote?

Regards,
Anton

Hi,

I have a storage device (hard disk) that is accessable from more then one
machine in the same time (let’s assume it’s a SCSI hard disk on shared
SCSI
bus). While the device is only readen everything is OK, but how can I make
this device writable by more then one client in the same time? How to keep
the file caches consistant? Any ideas? Anybody works with clusters here?
File system drive will not work I need to use existing one (maybe modified
with filter driver but I’d prefer not to do so…)

Regards,
Anton

P.S. For now I do store the written data in the different space so the
hard
disk is “partially shared”. Only the data that was never touched by
writing.

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2

Cross posting is not allowed on these lists. I think we all read both
lists.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton Kolomyeytsev
Sent: Thursday, February 21, 2002 6:21 AM
To: File Systems Developers
Subject: [ntfsd] How to share storage device on logical block access
level?

Hi,

Originally posted to ntdev list, maybe somebody here will be able to add

something to what guys in ntdev list wrote?

Regards,
Anton

Hi,

I have a storage device (hard disk) that is accessable from more then
one machine in the same time (let’s assume it’s a SCSI hard disk on
shared
SCSI
bus). While the device is only readen everything is OK, but how can I
make this device writable by more then one client in the same time? How
to keep the file caches consistant? Any ideas? Anybody works with
clusters here?
File system drive will not work I need to use existing one (maybe
modified with filter driver but I’d prefer not to do so…)

Regards,
Anton

P.S. For now I do store the written data in the different space so the
hard
disk is “partially shared”. Only the data that was never touched by
writing.

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3

I don’t subscribe to ntdev. I have better uses of my time than sorting through all the noise.

-----Original Message-----
From: Jamey Kirby [mailto:xxxxx@storagecraft.com]
Sent: Thursday, February 21, 2002 10:49 AM
To: File Systems Developers
Subject: [ntfsd] RE: How to share storage device on logical block access
level?

Cross posting is not allowed on these lists. I think we all read both
lists.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton Kolomyeytsev
Sent: Thursday, February 21, 2002 6:21 AM
To: File Systems Developers
Subject: [ntfsd] How to share storage device on logical block access
level?

Hi,

Originally posted to ntdev list, maybe somebody here will be able to add

something to what guys in ntdev list wrote?

Regards,
Anton

Hi,

I have a storage device (hard disk) that is accessable from more then
one machine in the same time (let’s assume it’s a SCSI hard disk on
shared
SCSI
bus). While the device is only readen everything is OK, but how can I
make this device writable by more then one client in the same time? How
to keep the file caches consistant? Any ideas? Anybody works with
clusters here?
File system drive will not work I need to use existing one (maybe
modified with filter driver but I’d prefer not to do so…)

Regards,
Anton

P.S. For now I do store the written data in the different space so the
hard
disk is “partially shared”. Only the data that was never touched by
writing.

You are currently subscribed to ntfsd as: xxxxx@storagecraft.com To
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4

Maybe, but cross-posting is not allowed on these lists; right Peter?

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Fuller, Rob
Sent: Thursday, February 21, 2002 8:00 AM
To: File Systems Developers
Subject: [ntfsd] RE: How to share storage device on logical block access
level?

I don’t subscribe to ntdev. I have better uses of my time than sorting
through all the noise.

-----Original Message-----
From: Jamey Kirby [mailto:xxxxx@storagecraft.com]
Sent: Thursday, February 21, 2002 10:49 AM
To: File Systems Developers
Subject: [ntfsd] RE: How to share storage device on logical block access
level?

Cross posting is not allowed on these lists. I think we all read both
lists.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton Kolomyeytsev
Sent: Thursday, February 21, 2002 6:21 AM
To: File Systems Developers
Subject: [ntfsd] How to share storage device on logical block access
level?

Hi,

Originally posted to ntdev list, maybe somebody here will be able to add

something to what guys in ntdev list wrote?

Regards,
Anton

Hi,

I have a storage device (hard disk) that is accessable from more then
one machine in the same time (let’s assume it’s a SCSI hard disk on
shared
SCSI
bus). While the device is only readen everything is OK, but how can I
make this device writable by more then one client in the same time? How
to keep the file caches consistant? Any ideas? Anybody works with
clusters here?
File system drive will not work I need to use existing one (maybe
modified with filter driver but I’d prefer not to do so…)

Regards,
Anton

P.S. For now I do store the written data in the different space so the
hard
disk is “partially shared”. Only the data that was never touched by
writing.

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5

On 02/21/02, ““Anton Kolomyeytsev” ” wrote:
> Hi,
>
> I have a storage device (hard disk) that is accessable from more then one
> machine in the same time (let’s assume it’s a SCSI hard disk on shared
> SCSI
> bus). While the device is only readen everything is OK, but how can I make
> this device writable by more then one client in the same time? How to keep
> the file caches consistant? Any ideas? Anybody works with clusters here?
> File system drive will not work I need to use existing one (maybe modified
> with filter driver but I’d prefer not to do so…)
>
> Regards,
> Anton
>
> P.S. For now I do store the written data in the different space so the
> hard
> disk is “partially shared”. Only the data that was never touched by
> writing.
>
> —
I worked on “Digital Clusters for Windows NT” several years ago, and we
determined that there was no simple answer. Thus we developed the
“sequential sharing” model for shared SCSI disk usage, which MSCS still
uses today. At any given time, only one node is allowed to access a shared
disk.

Many other people have replied, but only Andy Champ has given you a clue
about the answer. The answer is - you can’t do it without a true cluster
filesystem, running on all computers sharing the disk, and communicating
with each other. Other operating systems have achieved this in the past
(the classic is DEC’s VMS Clusters, released in 1984). But as of today, no
commercial cluster filesytem has been released for NT.

You could not get the right results with a simple filter driver, and might
even have troubles with a full filesytstem driver too, since the NT cache
manager is also involved in writing to disk.

Good luck!
Carl Appellof
VERITAS Software Global Corporation

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6

This is really getting far afield of the original subject, but OSR’s Lyris
server will catch a *real* crosspost, even if they are just the same
message sent to more than one list. It does this by looking for multiple
lists in the TO:, CC:, and BCC: fields. It also compares the first line of
the *body* to previous messages, and if they match, it’s considered a
crosspost. I don’t know how long the list of previous messages is. Peter
probably knows.

All that said, I didn’t consider the original message on this thread a
cross-post at all, since he posted to one list, didn’t get any answers,
then tried another list. If that’s not a valid usage of these lists, then
we should all go home.

Phil

“Maxim S. Shatskih” @lists.osr.com on 02/28/2002
06:07:26 PM

Please respond to “File Systems Developers”

Sent by: xxxxx@lists.osr.com

To: “File Systems Developers”
cc:

Subject: [ntfsd] RE: How to share storage device on logical block
access level?

> He didn’t commit the henious cross-post, as that would be sending the
> same message to both lists at the same time. He posted to ntdev, and got

I personally just press “Reply To All” button.
So, if the original poster xposted, I will too.
I also attend both lists. Any decent NT kmode developer must IMHO.

Max

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