Disk Shadowing and Mirroring

classic Classic list List threaded Threaded
3 messages Options
Reply | Threaded
Open this post in threaded view
|

Disk Shadowing and Mirroring

Mailkc
CONTENTS DELETED
The author has deleted this message.
Reply | Threaded
Open this post in threaded view
|

Re: [CCCure CISSP] Disk Shadowing and Mirroring

Marouane

 Mirroring duplicates data on other disks, it is EXPENSIVE way of using disk space, it is the LEAST efficient. It is RAID 1 (think of it that way). In the CISSP world, shadowing is often associated with the database which is the real time or live processing of transactions, and it also duplicates data. It is also called database shadowing (think of it as duplicating database sets)

Which one is faster really depends on factors such as what type of underlined RAID you are using. For example, if you are using RAID 0, although it is not fault tolerant, it will have the faster writes. Last but not least, mirroring speed may also be affected by what type of connections you have in the case of remote journaling (for example) because you are mirroring transactions processing over certain type of connections.


Hope this helps -


Marouane




On Tue, Jan 21, 2014 at 7:46 AM, Mailkc <[hidden email]> wrote:
Hi All,

I have this question - If Disk Shadowing is different from Database
shadowing? What is the key difference between shadowing and Mirroring? Which
one is faster Disk Shadowing or Disk Mirroring and why?


Also I have come across different definitions of Disk Shadowing, where I
have the confusion - Shon says in shadowing all disks are considered as one
and data is written to all disks by the user and Eric says data is mirrored
from the primary disk and users do not access it.

Definitions below -

ISC2 Third Edition -

Database shadowing is the technique in which updates are shadowed in
multiple locations. It is like copying the entire database on to a remote
location.

Eric Conard Book;
A shadow database mirrors all changes made to a primary database but clients
do not access it.
Unlike replicated databases, the shadow database is one-way (data flows from
primary to shadow)

Shon Harris:
Disk Shadowing: When a user writes data to be stored on this media, the data
are written to all disks in the shadow set.

Any response would be highly appreciated.
Thanks.







--
View this message in context: http://cissp-study.3965.n7.nabble.com/Disk-Shadowing-and-Mirroring-tp544.html
Sent from the CISSP_Study mailing list archive at Nabble.com.

_______________________________________________
You can find the list archive at:
http://cissp-study.3965.n7.nabble.com/

CISSPstudy mailing list
[hidden email]

To UNSUBSCRIBE, SUBSCRIBE, or MANAGE your accout visit the link below:
http://cccure.org/mailman/listinfo/cisspstudy_cccure.org


_______________________________________________
You can find the list archive at:
http://cissp-study.3965.n7.nabble.com/

CISSPstudy mailing list
[hidden email]

To UNSUBSCRIBE, SUBSCRIBE, or MANAGE your accout visit the link below:
http://cccure.org/mailman/listinfo/cisspstudy_cccure.org
Reply | Threaded
Open this post in threaded view
|

Re: [CCCure CISSP] Disk Shadowing and Mirroring

Doug Spindler

I’m sure this is not on the exam, but in the real world you should know RAID has reached the end of its useful life span for RAID arrays using 500 GB drives and larger.  For more information  Google RAID is DEAD.  Microsoft’s Simple Storage using Disk Parity is currently one of the best solutions.

 

 

From: CISSPstudy [mailto:[hidden email]] On Behalf Of Marouane
Sent: Tuesday, January 21, 2014 7:44 PM
To: The CISSP Study Mailing list
Subject: Re: [CCCure CISSP] Disk Shadowing and Mirroring

 

 Mirroring duplicates data on other disks, it is EXPENSIVE way of using disk space, it is the LEAST efficient. It is RAID 1 (think of it that way). In the CISSP world, shadowing is often associated with the database which is the real time or live processing of transactions, and it also duplicates data. It is also called database shadowing (think of it as duplicating database sets)

Which one is faster really depends on factors such as what type of underlined RAID you are using. For example, if you are using RAID 0, although it is not fault tolerant, it will have the faster writes. Last but not least, mirroring speed may also be affected by what type of connections you have in the case of remote journaling (for example) because you are mirroring transactions processing over certain type of connections.

 

Hope this helps -

 

Marouane

 

 

On Tue, Jan 21, 2014 at 7:46 AM, Mailkc <[hidden email]> wrote:

Hi All,

I have this question - If Disk Shadowing is different from Database
shadowing? What is the key difference between shadowing and Mirroring? Which
one is faster Disk Shadowing or Disk Mirroring and why?


Also I have come across different definitions of Disk Shadowing, where I
have the confusion - Shon says in shadowing all disks are considered as one
and data is written to all disks by the user and Eric says data is mirrored
from the primary disk and users do not access it.

Definitions below -

ISC2 Third Edition -

Database shadowing is the technique in which updates are shadowed in
multiple locations. It is like copying the entire database on to a remote
location.

Eric Conard Book;
A shadow database mirrors all changes made to a primary database but clients
do not access it.
Unlike replicated databases, the shadow database is one-way (data flows from
primary to shadow)

Shon Harris:
Disk Shadowing: When a user writes data to be stored on this media, the data
are written to all disks in the shadow set.

Any response would be highly appreciated.
Thanks.







--
View this message in context: http://cissp-study.3965.n7.nabble.com/Disk-Shadowing-and-Mirroring-tp544.html
Sent from the CISSP_Study mailing list archive at Nabble.com.

_______________________________________________
You can find the list archive at:
http://cissp-study.3965.n7.nabble.com/

CISSPstudy mailing list
[hidden email]

To UNSUBSCRIBE, SUBSCRIBE, or MANAGE your accout visit the link below:
http://cccure.org/mailman/listinfo/cisspstudy_cccure.org

 


_______________________________________________
You can find the list archive at:
http://cissp-study.3965.n7.nabble.com/

CISSPstudy mailing list
[hidden email]

To UNSUBSCRIBE, SUBSCRIBE, or MANAGE your accout visit the link below:
http://cccure.org/mailman/listinfo/cisspstudy_cccure.org