Chris,
The TLD terminology is confusing so let's think about this way:
Performance is best when only 3-9 physical devices are included in
each mirror or RAIDZ grouping as shown in the configuration guide.
Cindy
On 12/01/09 09:53, Christopher White wrote:
Cindy --
Thanks for the link!
I see in one of the examples that there are 14 TLDs (all mirrored).
Does that mean there are no performance issues with having more than 9
TLDs? In the Sun class I attended, the instructor said to not use more
than 9 TLDs, which seems like it could be very limiting, especially in a
SAN setting. Like I said, our storage group presents 15G LUNs to use --
so it'd be difficult to keep the TLDs under 9 and have a very large
filesystem.
Let me know what you think. Thanks!
Chris
On Tue, Dec 1, 2009 at 10:47 AM, Cindy Swearingen
<cindy.swearin...@sun.com <mailto:cindy.swearin...@sun.com>> wrote:
Hi Chris,
If you have 40 or so disks then you would create 5-6 RAIDZ virtual
devices of 7-8 disks each, or possibly include two disks for the root
pool, two disks as spares, and then 36 (4 RAIDZ vdevs of 6 disks) disks
for a non-root pool.
This configuration guide hasn't been updated for RAIDZ-3 yet, but you
will get some ideas about how to configure a redundant configuration
of many disks, here:
http://www.solarisinternals.com/wiki/index.php/ZFS_Configuration_Guide
See ZFS Configuration Example (x4500 with raidz2)
Cindy
On 12/01/09 09:20, Christopher White wrote:
All,
We're going to start testing ZFS and I had a question about Top
Level Devices (TLDs). In Sun's class, they specifically said
not to use more than 9 TLDs due to performance concerns. Our
storage admins make LUNs roughly 15G in size -- so how would we
make a large pool (1TB) if we're limited to only 9 TLDs?
The Best Practices guide (
http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide#Storage_Pool_Performance_Considerations
) suggests not using 40+ disks in a RAIDZ TLD:
"Avoid creating a RAIDZ, RAIDZ-2, RAIDZ-3, or a mirrored
configuration with one logical device of 40+ devices. See the
sections below for examples of redundant configurations."
Does that mean we should only have 9 RAIDZ TLDs with 39 LUNs in
each RAIDZ?
Or is the 9 TLDs an old recommendation that has since been changed?
Thanks!
Chris
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