zfs discuss - Aug 2007 - ? ZFS dynamic striping over RAID-Z

Hi

if I create a storage pool with multiple RAID-Z stripes in it does ZFS 
dynamically stripe data across all the RAID-Z stripes in the pool 
automagically ?

If I relate this back to my storage array experience, this would be 
"Plaiding" which is/was creating a RAID-0 logical volume across
multiple
h/ware RAID-5 stripes.

Thanks

Tim

Tim Thomas wrote:
> if I create a storage pool with multiple RAID-Z stripes in it does ZFS 
> dynamically stripe data across all the RAID-Z stripes in the pool 
> automagically ?
>
> If I relate this back to my storage array experience, this would be 
> "Plaiding" which is/was creating a RAID-0 logical volume across
multiple
> h/ware RAID-5 stripes.
>   
I did this one week ago, while trying to get at least bit of random read
performance out of a X4500. Normal RAIDZ(2) performance has been between
0.8 and 5 MB/s, which was way too slow for our needs, so I used striped
RAIDZ to get a boost.

My test configuration:

c5t0/t4: system (mirrored)
c5t1/t5 - c5t3/t7: AVS bitmap volumes (mirrored)

This left 40 disks. I''ve created 13x RAIDZ with 3 disks each,
that''s 39
disks in total. The script I used is appended below.

And yes, it results in striped RAIDZ arrays (I call it "RAIDZ0"). And
my
data throughput was 13 times higher, as expected.

Hope this will help you a bit.

---
#!/bin/sh

/usr/sbin/zpool create -f big raidz c0t0d0s0 c1t0d0s0 c4t0d0s0 spare
c7t7d0s0
/usr/sbin/zpool add -f big raidz c6t0d0s0 c7t0d0s0 c0t1d0s0
/usr/sbin/zpool  add -f big raidz c1t1d0s0 c4t1d0s0 c6t1d0s0
/usr/sbin/zpool  add -f big raidz c7t1d0s0 c0t2d0s0 c1t2d0s0
/usr/sbin/zpool  add -f big raidz c4t2d0s0 c6t2d0s0 c7t2d0s0
/usr/sbin/zpool  add -f big raidz c0t3d0s0 c1t3d0s0 c4t3d0s0
/usr/sbin/zpool  add -f big raidz c6t3d0s0 c7t3d0s0 c0t4d0s0
/usr/sbin/zpool  add -f big raidz c1t4d0s0 c4t4d0s0 c6t4d0s0
/usr/sbin/zpool  add -f big raidz c7t4d0s0 c0t5d0s0 c1t5d0s0
/usr/sbin/zpool  add -f big raidz c4t5d0s0 c6t5d0s0 c7t5d0s0
/usr/sbin/zpool  add -f big raidz c0t6d0s0 c1t6d0s0 c4t6d0s0
/usr/sbin/zpool  add -f big raidz c6t6d0s0 c7t6d0s0 c0t7d0s0
/usr/sbin/zpool  add -f big raidz c1t7d0s0 c4t7d0s0 c6t7d0s0

/usr/sbin/zpool status
---


-- 

Ralf Ramge
Senior Solaris Administrator, SCNA, SCSA

Tel. +49-721-91374-3963
ralf.ramge at webde.de - http://web.de/

1&1 Internet AG
Brauerstra?e 48
76135 Karlsruhe

Amtsgericht Montabaur HRB 6484

Vorstand: Henning Ahlert, Ralph Dommermuth, Matthias Ehrlich, Andreas 
Gauger, Matthias Greve, Robert Hoffmann, Norbert Lang, Achim Weiss
Aufsichtsratsvorsitzender: Michael Scheeren

ZFS will stripe across all Root Level VDEVs, regardless of type of VDEV
(mirror, raidz, single whole disk, disk slices, whatever).

e.g.

tank01
  mirror
   c1t0d0
   c1t1d0
  raidz
   c1t2d0
   c1t3d0
   c1t4d0
  mirror
   c0t0d0s7
   c0t1d0s7

Should give you 3 stripes.


--
Sean

-----Original Message-----
From: zfs-discuss-bounces at opensolaris.org
[mailto:zfs-discuss-bounces at opensolaris.org] On Behalf Of Tim Thomas
Sent: Thursday, August 02, 2007 7:00 AM
To: ZFS Discuss
Subject: [zfs-discuss] ? ZFS dynamic striping over RAID-Z

Hi

if I create a storage pool with multiple RAID-Z stripes in it does ZFS
dynamically stripe data across all the RAID-Z stripes in the pool
automagically ?

If I relate this back to my storage array experience, this would be
"Plaiding" which is/was creating a RAID-0 logical volume across
multiple
h/ware RAID-5 stripes.

Thanks

Tim
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