does Ghost restore previous raid stripe size?

[Wayne]

I just moved my two raid 0 disks from the Asus A8V Promise controller to
the VIA controller. Saw a 15% speed gain (from 65 to 76 MB/second
according to HDTach, from two WD 80GB SATA disks). Also burst rate
increased from 112MB/sec to 161MB/second.

When rebuilding the raid array, I specifically reduced stripe size from
64KB to 32KB. I suppose my mistake is possible, because it is now
reported as 64KB again.

I restored the XP system with Ghost 2003. Does Ghost restore also reset
stripe size? Guessing, but I suppose it is just some bytes on the
Master Boot Record, and might do it? Any way around that?

 

[David H. Lipman]

From: "Wayne" <[email protected]>

| I just moved my two raid 0 disks from the Asus A8V Promise controller to
| the VIA controller. Saw a 15% speed gain (from 65 to 76 MB/second
| according to HDTach, from two WD 80GB SATA disks). Also burst rate
| increased from 112MB/sec to 161MB/second.
|
| When rebuilding the raid array, I specifically reduced stripe size from
| 64KB to 32KB. I suppose my mistake is possible, because it is now
| reported as 64KB again.
|
| I restored the XP system with Ghost 2003. Does Ghost restore also reset
| stripe size? Guessing, but I suppose it is just some bytes on the
| Master Boot Record, and might do it? Any way around that?
|

No. In fact it is NOT suggested to use with RAID.
ftp://ftp.symantec.com/public/english_us_canada/products/ghost/manuals/

 

[Leythos]

From: "Wayne" <[email protected]>

| I just moved my two raid 0 disks from the Asus A8V Promise controller to
| the VIA controller. Saw a 15% speed gain (from 65 to 76 MB/second
| according to HDTach, from two WD 80GB SATA disks). Also burst rate
| increased from 112MB/sec to 161MB/second.
|
| When rebuilding the raid array, I specifically reduced stripe size from
| 64KB to 32KB. I suppose my mistake is possible, because it is now
| reported as 64KB again.
|
| I restored the XP system with Ghost 2003. Does Ghost restore also reset
| stripe size? Guessing, but I suppose it is just some bytes on the
| Master Boot Record, and might do it? Any way around that?
|

No. In fact it is NOT suggested to use with RAID.
ftp://ftp.symantec.com/public/english_us_canada/products/ghost/manuals/

While it's not a recommended method, I've used it hundreds of times
without any problems on hardware RAID arrays - and it will resize the
clusters as you resize the partitions.

 

[Wayne]

No. In fact it is NOT suggested to use with RAID.
ftp://ftp.symantec.com/public/english_us_canada/products/ghost/manuals/

We should inform Symantec that they are clearly wrong then. Because
on the A8V motherboard, Ghost 2003 works great with both the Promise raid
controller and the VIA raid controller. Nothing extra is required, simply
boot on the Ghost CD, and there it is, ready to go.

I would guess there is indeed a huge problem with plugin Raid cards, but in
the A8V case, I suppose Ghost is just accessing the BIOS, and the BIOS is
accessing the RAID drives, in the same way Ghost and Dos sees USB drives.
It sure appears that Ghost 2003 can access any of these drives seen by the
BIOS. In this case, I doubt Ghost even knows or cares that the drive is
RAID or SATA, but nevertheless, backup and restore works great to it. At
least my Ghost 2003 restores to AV8 RAID SATA drives have been perfect, on
both the Promise and VIA controllers. No way I am going back now.

Except I am still puzzled why my supposed change to 32KB block size came
out as the previous 64KB again after the Ghost restore to it. It may have
been my mistake somehow, or perhaps Ghost simply restores that too ?

 

[David H. Lipman]

From: "Leythos" <[email protected]>

|
| While it's not a recommended method, I've used it hundreds of times
| without any problems on hardware RAID arrays - and it will resize the
| clusters as you resize the partitions.
|
| --
|
| (e-mail address removed)
| remove 999 in order to email me

Hardware RAID is different. The hardware has its own CPU and OS and translates what it sees
back to the computer's OS as a virtual drive. One of the *many* reasons why hardware RAID
is better than RAID built into the OS.

 

[edavid3001]

While we have used GHOST with RAID drives many times, we have seen
cases where it does not work correctly.

I think Symantec doesn't officially support RAID so they don't get the
support calls.

 

[John]

We should inform Symantec that they are clearly wrong then. Because
on the A8V motherboard, Ghost 2003 works great with both the Promise raid
controller and the VIA raid controller. Nothing extra is required, simply
boot on the Ghost CD, and there it is, ready to go.

I would guess there is indeed a huge problem with plugin Raid cards, but in
the A8V case, I suppose Ghost is just accessing the BIOS, and the BIOS is
accessing the RAID drives, in the same way Ghost and Dos sees USB drives.
It sure appears that Ghost 2003 can access any of these drives seen by the
BIOS. In this case, I doubt Ghost even knows or cares that the drive is
RAID or SATA, but nevertheless, backup and restore works great to it. At
least my Ghost 2003 restores to AV8 RAID SATA drives have been perfect, on
both the Promise and VIA controllers. No way I am going back now.

Except I am still puzzled why my supposed change to 32KB block size came
out as the previous 64KB again after the Ghost restore to it. It may have
been my mistake somehow, or perhaps Ghost simply restores that too ?

I think when Ghost makes a clone it has a predefined cluster size (varying
depending on the partition size). I suspect you can override it with command
line options.

 

[Wayne]

I think when Ghost makes a clone it has a predefined cluster size (varying
depending on the partition size). I suspect you can override it with command
line options.

Thanks John. I wasnt clear enough, but there are two "block sizes". One is
the regular disk cluster size, normally determined when any disk partition is
formatted, and I think you are speaking of that.

Then when you declare a RAID 0 array, the RAID controller has a block size,
also called "stripe size", which is the block size RAID alternately writes to
the two disks. Anything smaller than this RAID block size simply just goes
to one disk, even in a RAID 0 striped set. On the Asus AV8 motherboard, the
Promise RAID controller is always 64KB, but the VIA RAID controller can be
set over a range, I think 4KB to 64KB. My NTFS disks have 4K clusters either
way.

When I moved the disk array from Promise to VIA, I could and did lower the
stripe size to 32KB, but after the Ghost restore, it now says 64KB again.
I'm assuming Ghost also "restored" that value, but am not sure what happened,
or even why it would care.