Mailing List Archive

After learning about how our data grows....

We are going to 2 disk Vol 0 (mirrored disk)

Just so that we don't have to jeopardize any data volumes
when we upgrade the DATAONTAP OS. Also, I am not remembering
why at the time, there is a condition when the reboot time
is related to the size of vol0.

I keep a spare for each volume as a policy. I wouldn't have
a volume of less than 7 disk (except for vol0).

Have fun,

Joe




At 11:24 AM 8/7/2002 -0400, devnull@adc.idt.com wrote:
>I am trying to decide on the number of volumes for our F810 which has a
>DS14 shelf(FC-AL), with 14 36G drives.
>
>By default Ontap puts 8 disks in a RAID group.
>
>I guess i am trying to figure out if
>
>
>* I should have 2 volumes vol0 and vol1, one with 8 disks and one with 5
> disks and i have ONE spare for both the volumes
> (Is this safe in terms of ratio of disks used to spares ? )
>
>* Have 2 volumes(6 + 6) and 2 spares
>
>* Have 1 volume with 13 disks and 1 spare. (reconstruction time on
> failed disk would be high, and i dont know if there will be performance
> issues esp in calculating parity etc)
>
>
>
>Other suggestions are welcome too.
>
>Many Thanks,
>
>Regards,
>
>/dev/null

If it was me I would use 2 disks as vol0 and not keep any business critical
data on it, and use the remaining disks in vol1 (with 9 disks per RAID group)
with 1 disk as spare. You would be very unlucky to need 2 spares! I have 1
spare for my 28 disks. Reconstruction time shouldn't be much of an issue
should it?

Matt

devnull@adc.idt.com wrote:

> I am trying to decide on the number of volumes for our F810 which has a
> DS14 shelf(FC-AL), with 14 36G drives.
>
> By default Ontap puts 8 disks in a RAID group.
>
> I guess i am trying to figure out if
>
> * I should have 2 volumes vol0 and vol1, one with 8 disks and one with 5
> disks and i have ONE spare for both the volumes
> (Is this safe in terms of ratio of disks used to spares ? )
>
> * Have 2 volumes(6 + 6) and 2 spares
>
> * Have 1 volume with 13 disks and 1 spare. (reconstruction time on
> failed disk would be high, and i dont know if there will be performance
> issues esp in calculating parity etc)
>
> Other suggestions are welcome too.
>
> Many Thanks,
>
> Regards,
>
> /dev/null

devnull@adc.idt.com wrote:

> I am trying to decide on the number of volumes for our F810 which has a
> DS14 shelf(FC-AL), with 14 36G drives.
>
> By default Ontap puts 8 disks in a RAID group.
>
> I guess i am trying to figure out if
>
>
> * I should have 2 volumes vol0 and vol1, one with 8 disks and one with 5
> disks and i have ONE spare for both the volumes
> (Is this safe in terms of ratio of disks used to spares ? )
>
> * Have 2 volumes(6 + 6) and 2 spares
>
> * Have 1 volume with 13 disks and 1 spare. (reconstruction time on
> failed disk would be high, and i dont know if there will be performance
> issues esp in calculating parity etc)
>
>



hi,

all 3 configs are ok ! u have to choose which will meet u best.

1. the more volumes the more space u give away for the parity disk of
each raidgroup
2. u have a service contract ? when u will get new parts ?
no contract = 2 spares
3. R/W performance is better on bigger volumes with more spindles...
4. reconstrution is normal no performance issue, but in this time while
reconstructing, the disks have more work to do and the chance to get a
second disk break increases

why dont u build 1 volume with 8 (for better performance), 1 with 4
(expandable for future) and 2 spares ?

hope this helps

/dev/zero


>
> Other suggestions are welcome too.
>
> Many Thanks,
>
> Regards,
>
> /dev/null
>

On Wed, Aug 07, 2002 at 11:24:19AM -0400, devnull@adc.idt.com wrote:
> I am trying to decide on the number of volumes for our F810 which has a
> DS14 shelf(FC-AL), with 14 36G drives.
>
> By default Ontap puts 8 disks in a RAID group.
>
> I guess i am trying to figure out if
>
>
> * I should have 2 volumes vol0 and vol1, one with 8 disks and one with 5
> disks and i have ONE spare for both the volumes
> (Is this safe in terms of ratio of disks used to spares ? )
>
> * Have 2 volumes(6 + 6) and 2 spares
>
> * Have 1 volume with 13 disks and 1 spare. (reconstruction time on
> failed disk would be high, and i dont know if there will be performance
> issues esp in calculating parity etc)
>

Personally, I only put archive data on vol0. This gives me a small bit
of online archival space without worry of a rouge script killing me.
The raid set size on 36G drives is suggested to be 10 (by NetApp) so if
you did a 2 disk raids set on vol0 (1d+1p) and then vol2 with remaining - spares
this would probably meet your needs. I like what someone else said about
your support contract dictating the number of spares you keep. Also, if you
have data that doesn't change frequently you could consider reducing the
snap reserve from the 20% that comes with DOT to something more reasonable
for your environment.
C-

>
>
> Other suggestions are welcome too.
>
> Many Thanks,
>
> Regards,
>
> /dev/null
>

--
-----------------------------------------------------------------------------
* | *
* Chris Blackmor _______ | Good judgment comes from *
* Advanced Micro Devices \____ | | experience *
* Phone: (512) 602-1608 /| | | | And a lot of that comes *
* Fax: (512) 602-5155 | |___| | | from *
* Email: chris.blackmor@amd.com |____/ \| | bad judgment! *
* | Author Unknown*
-----------------------------------------------------------------------------
* My comments are mine, and mine alone. *
-----------------------------------------------------------------------------

We usually run with one spare for our filers, regardless of the number of disks. When I recently asked for a quote from Netapp, the sales contact suggested 3 spares for a 10 shelf system and that it was risky to run with just 1, which we've never heard from them before.

I'm not sure why its risky. We've been running this way for years, with no issues. With next day shipment of replacement disks it doesn't seem to be an issue

So how many spares do people use/recommend?

Dave

-----Original Message-----
From: Matt Musgrove [mailto:matt.musgrove@thales-is.com]
Sent: 07 August 2002 17:11
To: devnull@adc.idt.com
Cc: toasters@mathworks.com
Subject: Re: # of Volumes.

If it was me I would use 2 disks as vol0 and not keep any business critical
data on it, and use the remaining disks in vol1 (with 9 disks per RAID group)
with 1 disk as spare. You would be very unlucky to need 2 spares! I have 1
spare for my 28 disks. Reconstruction time shouldn't be much of an issue
should it?

Matt

devnull@adc.idt.com wrote:

> I am trying to decide on the number of volumes for our F810 which has a
> DS14 shelf(FC-AL), with 14 36G drives.
>
> By default Ontap puts 8 disks in a RAID group.
>
> I guess i am trying to figure out if
>
> * I should have 2 volumes vol0 and vol1, one with 8 disks and one with 5
> disks and i have ONE spare for both the volumes
> (Is this safe in terms of ratio of disks used to spares ? )
>
> * Have 2 volumes(6 + 6) and 2 spares
>
> * Have 1 volume with 13 disks and 1 spare. (reconstruction time on
> failed disk would be high, and i dont know if there will be performance
> issues esp in calculating parity etc)
>
> Other suggestions are welcome too.
>
> Many Thanks,
>
> Regards,
>
> /dev/null

On Wed, Aug 07, 2002 at 08:39:07PM +0100, Heiland, David Joseph (Dave) wrote:
>
> We usually run with one spare for our filers, regardless of the number of disks. When I recently asked for a quote from Netapp, the sales contact suggested 3 spares for a 10 shelf system and that it was risky to run with just 1, which we've never heard from them before.
>
> I'm not sure why its risky. We've been running this way for years, with no issues. With next day shipment of replacement disks it doesn't seem to be an issue
>
> So how many spares do people use/recommend?

I like to have 1 per volume. The probability that 2 disks from the
same volume will die in succession is comfortably low.

Igor

If you consider the dropping prices on used 9gb/18gb/36gb NetApp disks,
there's little reason to scrimp on an additional spare drive and/or drive
shelf.

Scott

Scott Fischmann
Union Computer Exchange, Inc.
6233 Idylwood Lane
Minneapolis, MN 55436
email: scott@unioncomputer.com
phone: 952 935 7282 | fax: 952 935 5056

> Subj:RE: # of Volumes.
> Date:8/7/2002 3:06:28 PM Central Standard Time
> From:<A HREF="mailto:dheiland@lucent.com">dheiland@lucent.com</A>
> To:<A HREF="mailto:toasters@mathworks.com">toasters@mathworks.com</A>
> Sent from the Internet
>
>
>
>
> We usually run with one spare for our filers, regardless of the number of
> disks. When I recently asked for a quote from Netapp, the sales contact
> suggested 3 spares for a 10 shelf system and that it was risky to run with
> just 1, which we've never heard from them before.
>
> I'm not sure why its risky. We've been running this way for years, with no
> issues. With next day shipment of replacement disks it doesn't seem to be
> an issue
>
> So how many spares do people use/recommend?
>
> Dave
>
> -----Original Message-----
> From: Matt Musgrove [mailto:matt.musgrove@thales-is.com]
> Sent: 07 August 2002 17:11
> To: devnull@adc.idt.com
> Cc: toasters@mathworks.com
> Subject: Re: # of Volumes.
>
> If it was me I would use 2 disks as vol0 and not keep any business critical
> data on it, and use the remaining disks in vol1 (with 9 disks per RAID
> group)
> with 1 disk as spare. You would be very unlucky to need 2 spares! I have
> 1
> spare for my 28 disks. Reconstruction time shouldn't be much of an issue
> should it?
>
> Matt
>
> devnull@adc.idt.com wrote:
>
> > I am trying to decide on the number of volumes for our F810 which has a
> > DS14 shelf(FC-AL), with 14 36G drives.
> >
> > By default Ontap puts 8 disks in a RAID group.
> >
> > I guess i am trying to figure out if
> >
> > * I should have 2 volumes vol0 and vol1, one with 8 disks and one with 5
> > disks and i have ONE spare for both the volumes
> > (Is this safe in terms of ratio of disks used to spares ? )
> >
> > * Have 2 volumes(6 + 6) and 2 spares
> >
> > * Have 1 volume with 13 disks and 1 spare. (reconstruction time on
> > failed disk would be high, and i dont know if there will be performance
> > issues esp in calculating parity etc)
> >
> > Other suggestions are welcome too.
> >
> > Many Thanks,
> >
> > Regards,
> >
> > /dev/null
>