On Wed, 2009-09-16 at 14:19 -0700, Richard Elling wrote:
> Actually, I had a ton of data on resilvering which shows mirrors and
> raidz equivalently bottlenecked on the media write bandwidth. However,
> there are other cases which are IOPS bound (or CR bound :-) which
> cover some of the postings
On Thu, Sep 17, 2009 at 11:41 AM, Adam Leventhal wrote:
> RAID-3 bit-interleaved parity (basically not used)
There was a hardware RAID chipset that used RAID-3. Netcell Revolution
I think it was called.
It looked interesting and I thought about grabbing one at the time but
never got arou
On Thu, Sep 17, 2009 at 01:32:43PM +0200, Eugen Leitl wrote:
> > reasons), you will lose 2 disks worth of storage to parity leaving 12
> > disks worth of data. With raid10 you will lose half, 7 disks to
> > parity/redundancy. With two raidz2 sets, you will get (5+2)+(5+2), that
> > is 5+5 disks wor
rswwal...@gmail.com said:
> It's not the stripes that make a difference, but the number of controllers
> there.
>
> What's the system config on that puppy?
The "zpool status -v" output was from a Thumper (X4500), slightly edited,
since in our real-world Thumper, we use c6t0d0 in c5t4d0's place i
Darren J Moffat wrote:
Erik Trimble wrote:
So SSDs for ZIL/L2ARC don't bring that much when used with
raidz2/raidz3,
if I write a lot, at least, and don't access the cache very much,
according
to some recent posts on this list.
Not true.
Remember: ZIL = write cache
ZIL is NOT a write c
Erik Trimble wrote:
So SSDs for ZIL/L2ARC don't bring that much when used with raidz2/raidz3,
if I write a lot, at least, and don't access the cache very much,
according
to some recent posts on this list.
Not true.
Remember: ZIL = write cache
ZIL is NOT a write cache. The ZIL is the In
On Thu, Sep 17, 2009 at 12:55:35PM +0200, Tomas Ögren wrote:
> It's not a fixed value per technology, it depends on the number of disks
> per group. RAID5/RAIDZ1 "loses" 1 disk worth to parity per group.
> RAID6/RAIDZ" loses 2 disks. RAIDZ3 loses 3 disks. Raid1/mirror loses
> half the disks. So in
Eugen Leitl wrote:
On Wed, Sep 16, 2009 at 08:02:35PM +0300, Markus Kovero wrote:
It's possible to do 3-way (or more) mirrors too, so you may achieve better
redundancy than raidz2/3
I understand there's almost no additional performance penalty to raidz3
over raidz2 in terms of CPU l
On 17 September, 2009 - Eugen Leitl sent me these 2,0K bytes:
> On Wed, Sep 16, 2009 at 08:02:35PM +0300, Markus Kovero wrote:
>
> > It's possible to do 3-way (or more) mirrors too, so you may achieve better
> > redundancy than raidz2/3
>
> I understand there's almost no additional performance
On Wed, Sep 16, 2009 at 10:23:01AM -0700, Richard Elling wrote:
> This line of reasoning doesn't get you very far. It is much better to
> take a look at
> the mean time to data loss (MTTDL) for the various configurations. I
> wrote a
> series of blogs to show how this is done.
> http://blogs
On Wed, Sep 16, 2009 at 08:02:35PM +0300, Markus Kovero wrote:
> It's possible to do 3-way (or more) mirrors too, so you may achieve better
> redundancy than raidz2/3
I understand there's almost no additional performance penalty to raidz3
over raidz2 in terms of CPU load. Is that correct?
So S
On Sep 16, 2009, at 7:17 PM, Ross Walker wrote:
more resilient to temporary path failures.
As another list member pointed out you could also avoid the issue by
having a raidz disk per controller. But if I'm buying that kind of
big iron I might just opt for a 3par or emc and save myself the
On Sep 16, 2009, at 6:43 PM, Bob Friesenhahn > wrote:
On Wed, 16 Sep 2009, Ross Walker wrote:
There is another type of failure that mirrors help with and that is
controller or path failures. If one side of a mirror set is on one
controller or path and the other on another then a failure of
On Sep 16, 2009, at 6:50 PM, Marion Hakanson wrote:
rswwal...@gmail.com said:
There is another type of failure that mirrors help with and that is
controller or path failures. If one side of a mirror set is on one
controller or path and the other on another then a failure of one
will not
t
rswwal...@gmail.com said:
> There is another type of failure that mirrors help with and that is
> controller or path failures. If one side of a mirror set is on one
> controller or path and the other on another then a failure of one will not
> take down the set.
>
> You can't get that with RAIDZ
On Wed, 16 Sep 2009, Ross Walker wrote:
There is another type of failure that mirrors help with and that is
controller or path failures. If one side of a mirror set is on one controller
or path and the other on another then a failure of one will not take down the
set.
You can't get that wit
On Sep 16, 2009, at 4:29 PM, "Marty Scholes"
wrote:
Yes. This is a mathematical way of saying
"lose any P+1 of N disks."
I am hesitant to beat this dead horse, yet it is a nuance that
either I have completely misunderstood or many people I've met have
completely missed.
Whether a str
On 09/16/09 14:19, Richard Elling wrote:
On Sep 16, 2009, at 1:09 PM, Bob Friesenhahn wrote:
On Wed, 16 Sep 2009, Thomas Burgess wrote:
hrm, i always thought raidz took longerlearn something every day =)
And you were probably right, in spite of Richard's lack of knowledge
of a study or
On Sep 16, 2009, at 1:29 PM, Marty Scholes wrote:
Yes. This is a mathematical way of saying
"lose any P+1 of N disks."
I am hesitant to beat this dead horse, yet it is a nuance that
either I have completely misunderstood or many people I've met have
completely missed.
Whether a stripe of
On Sep 16, 2009, at 1:09 PM, Bob Friesenhahn wrote:
On Wed, 16 Sep 2009, Thomas Burgess wrote:
hrm, i always thought raidz took longerlearn something every
day =)
And you were probably right, in spite of Richard's lack of knowledge
of a study or the feeling in his gut. Just look at t
> Yes. This is a mathematical way of saying
> "lose any P+1 of N disks."
I am hesitant to beat this dead horse, yet it is a nuance that either I have
completely misunderstood or many people I've met have completely missed.
Whether a stripe of mirrors or mirror of a stripes, any single failure m
On Wed, 16 Sep 2009, Thomas Burgess wrote:
hrm, i always thought raidz took longerlearn something every day =)
And you were probably right, in spite of Richard's lack of knowledge
of a study or the feeling in his gut. Just look at the many postings
here about resilvering and you will se
On Sep 16, 2009, at 12:50 PM, Marty Scholes wrote:
This line of reasoning doesn't get you very far.
It is much better to take a look at
the mean time to data loss (MTTDL) for the various
configurations. I wrote a
series of blogs to show how this is done.
http://blogs.sun.com/relling/tags/mttdl"
> This line of reasoning doesn't get you very far.
> It is much better to take a look at
> the mean time to data loss (MTTDL) for the various
> configurations. I wrote a
> series of blogs to show how this is done.
> http://blogs.sun.com/relling/tags/mttdl";
> target="_blank">http://blogs.sun.com
hrm, i always thought raidz took longerlearn something every day =)
On Wed, Sep 16, 2009 at 2:14 PM, Richard Elling wrote:
> On Sep 16, 2009, at 10:42 AM, Thomas Burgess wrote:
>
> Mirrors are much quicker to replace if one DOES fail though...so i would
>> think that bad stuff could happen
On Sep 16, 2009, at 10:42 AM, Thomas Burgess wrote:
Mirrors are much quicker to replace if one DOES fail though...so i
would think that bad stuff could happen with EITHER solutionIf
you buy a bunch of hard drives for a raidz and they are all from the
same batch they might all fail aroun
Mirrors are much quicker to replace if one DOES fail though...so i would
think that bad stuff could happen with EITHER solutionIf you buy a bunch
of hard drives for a raidz and they are all from the same batch they might
all fail around the same time...what if you have a raidz2 group and 2 driv
On Sep 16, 2009, at 9:38 AM, Marty Scholes wrote:
Generally speaking, striping mirrors will be faster
than raidz or raidz2,
but it will require a higher number of disks and
therefore higher cost to
The main reason to use
raidz or raidz2 instead
of striping mirrors would be to keep the cost down,
At the end of the day, it TOTALLY depends on your needs. raidz may be the
best bet for you if you simply do not need the speed of mirrors, and as
another user mentioned, it DOES offer better fault tollerence. Figure out
what your needs are for your workload THEN ask.
These type of loaded questio
On Wed, September 16, 2009 10:35, cindy.swearin...@sun.com wrote:
> Detaching disks from a mirror isn't ideal but if you absolutely have
> to reuse a disk temporarily then go with mirrors. See the output below.
> You can replace disks in either configuration if you want to switch
> smaller disks
38
To: zfs-discuss@opensolaris.org
Subject: Re: [zfs-discuss] RAIDZ versus mirrroed
> Generally speaking, striping mirrors will be faster
> than raidz or raidz2,
> but it will require a higher number of disks and
> therefore higher cost to
> The main reason to use
> raidz or raidz
> Generally speaking, striping mirrors will be faster
> than raidz or raidz2,
> but it will require a higher number of disks and
> therefore higher cost to
> The main reason to use
> raidz or raidz2 instead
> of striping mirrors would be to keep the cost down,
> or to get higher usable
> space out
On Wed, 16 Sep 2009, en...@businessgrade.com wrote:
Hi. If I am using slightly more reliable SAS drives versus SATA, SSDs for
both L2Arc and ZIL and lots of RAM, will a mirrored pool of say 24 disks hold
any significant advantages over a RAIDZ pool?
A mirrored pool will support more IOPs. Th
I think in theory the ZIL/L2ARC should make things nice and fast if your
workload includes sync requests (database, iscsi, nfs, etc.), regardless of the
backend disks. But the only sure way to know is test with your work load.
-Scott
--
This message posted from opensolaris.org
_
In addition, if you need the flexibility of moving disks around until
the device removal CR integrates, then mirrored pools are more flexible.
Detaching disks from a mirror isn't ideal but if you absolutely have
to reuse a disk temporarily then go with mirrors. See the output below.
You can repla
Quoting David Magda :
On Wed, September 16, 2009 10:31, Edward Ned Harvey wrote:
Hi. If I am using slightly more reliable SAS drives versus SATA, SSDs
for both L2Arc and ZIL and lots of RAM, will a mirrored pool of say 24
disks hold any significant advantages over a RAIDZ pool?
Generally spea
On Wed, September 16, 2009 10:31, Edward Ned Harvey wrote:
>> Hi. If I am using slightly more reliable SAS drives versus SATA, SSDs
>> for both L2Arc and ZIL and lots of RAM, will a mirrored pool of say 24
>> disks hold any significant advantages over a RAIDZ pool?
>
> Generally speaking, striping
> Hi. If I am using slightly more reliable SAS drives versus SATA, SSDs
> for both L2Arc and ZIL and lots of RAM, will a mirrored pool of say 24
> disks hold any significant advantages over a RAIDZ pool?
Generally speaking, striping mirrors will be faster than raidz or raidz2,
but it will require
it should be faster. It really depends on what you are using it for though,
I've been using raidz for my system and i'm very happy with it.
On Wed, Sep 16, 2009 at 8:55 AM, wrote:
> Hi. If I am using slightly more reliable SAS drives versus SATA, SSDs for
> both L2Arc and ZIL and lots of RAM,
39 matches
Mail list logo
