Re: [zfs-discuss] Multiple SLOG devices per pool

2010-10-13 Thread Ray Van Dolson
On Tue, Oct 12, 2010 at 08:49:00PM -0700, Edward Ned Harvey wrote:
  From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
  boun...@opensolaris.org] On Behalf Of Ray Van Dolson
  
  I have a pool with a single SLOG device rated at Y iops.
  
  If I add a second (non-mirrored) SLOG device also rated at Y iops will
  my zpool now theoretically be able to handle 2Y iops?  Or close to
  that?
 
 Yes.
 
 But we're specifically talking about sync mode writes.  Not async, and not
 read.  And we're not comparing apples to oranges etc, not measuring an
 actual number of IOPS, because of aggregation etc.  But I don't think that's
 what you were asking.  I don't think you are trying to quantify the number
 of IOPS.  I think you're trying to confirm the qualitative characteristic,
 If I have N slogs, I will write N times faster than a single slog.  And
 that's a simple answer.
 
 Yes.
 

Thanks. :)
___
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss


Re: [zfs-discuss] Multiple SLOG devices per pool

2010-10-12 Thread Edward Ned Harvey
 From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
 boun...@opensolaris.org] On Behalf Of Ray Van Dolson
 
 I have a pool with a single SLOG device rated at Y iops.
 
 If I add a second (non-mirrored) SLOG device also rated at Y iops will
 my zpool now theoretically be able to handle 2Y iops?  Or close to
 that?

Yes.

But we're specifically talking about sync mode writes.  Not async, and not
read.  And we're not comparing apples to oranges etc, not measuring an
actual number of IOPS, because of aggregation etc.  But I don't think that's
what you were asking.  I don't think you are trying to quantify the number
of IOPS.  I think you're trying to confirm the qualitative characteristic,
If I have N slogs, I will write N times faster than a single slog.  And
that's a simple answer.

Yes.

___
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss