Thanks — interesting reading.
Distilling the discussion there, below are my takeaways. Am I interpreting
correctly?
1) The spillover phenomenon and thus the small number of discrete sizes that
are effective without being wasteful — are recognized
2) "I don't think we should plan teh block.db
Btw, the original discussion leading to the 4% recommendation is here:
https://github.com/ceph/ceph/pull/23210
--
Paul Emmerich
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On Thu, Aug
30gb already includes WAL, see
http://yourcmc.ru/wiki/Ceph_performance#About_block.db_sizing
15 августа 2019 г. 1:15:58 GMT+03:00, Anthony D'Atri
пишет:
>Good points in both posts, but I think there’s still some unclarity.
>
>Absolutely let’s talk about DB and WAL together. By “bluestore goes
Hi Folks,
The basic idea behind the WAL is that for every DB write transaction you
first write it into an in-memory buffer and to a region on disk.
RocksDB typically is setup to have multiple WAL buffers, and when one or
more fills up, it will start flushing the data to L0 while new writes
Den tors 15 aug. 2019 kl 00:16 skrev Anthony D'Atri :
> Good points in both posts, but I think there’s still some unclarity.
>
...
> We’ve seen good explanations on the list of why only specific DB sizes,
> say 30GB, are actually used _for the DB_.
> If the WAL goes along with the DB,
Good points in both posts, but I think there’s still some unclarity.
Absolutely let’s talk about DB and WAL together. By “bluestore goes on flash”
I assume you mean WAL+DB?
“Simply allocate DB and WAL will appear there automatically”
Forgive me please if this is obvious, but I’d like to see a
On 8/14/19 1:06 PM, solarflow99 wrote:
Actually standalone WAL is required when you have either very
small fast
device (and don't want db to use it) or three devices (different in
performance) behind OSD (e.g. hdd, ssd, nvme). So WAL is to be
located
at the fastest one.
> Actually standalone WAL is required when you have either very small fast
> device (and don't want db to use it) or three devices (different in
> performance) behind OSD (e.g. hdd, ssd, nvme). So WAL is to be located
> at the fastest one.
>
> For the given use case you just have HDD and NVMe and
Hi Wido & Hermant.
On 8/14/2019 11:36 AM, Wido den Hollander wrote:
On 8/14/19 9:33 AM, Hemant Sonawane wrote:
Hello guys,
Thank you so much for your responses really appreciate it. But I would
like to mention one more thing which I forgot in my last email is that I
am going to use this
Hi,
please keep in mind that due to the rocksdb level concept, only certain
db partition sizes are useful. Larger partitions are a waste of
capacity, since rockdb will only use whole level sizes.
There has been a lot of discussion about this on the mailing list in the
last months. A plain
On 8/14/19 9:33 AM, Hemant Sonawane wrote:
> Hello guys,
>
> Thank you so much for your responses really appreciate it. But I would
> like to mention one more thing which I forgot in my last email is that I
> am going to use this storage for openstack VM's. So still the answer
> will be the
Hello guys,
Thank you so much for your responses really appreciate it. But I would like
to mention one more thing which I forgot in my last email is that I am
going to use this storage for openstack VM's. So still the answer will be
the same that I should use 1GB for wal?
On Wed, 14 Aug 2019 at
On 8/13/19 3:51 PM, Paul Emmerich wrote:
On Tue, Aug 13, 2019 at 10:04 PM Wido den Hollander wrote:
I just checked an RGW-only setup. 6TB drive, 58% full, 11.2GB of DB in
use. No slow db in use.
random rgw-only setup here: 12TB drive, 77% full, 48GB metadata and
10GB omap for index and
om
> > www.PerformAir.com
> >
> >
> >
> > -Original Message-
> > From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of
> > Wido den Hollander
> > Sent: Tuesday, August 13, 2019 12:51 PM
> > To: ceph-users@lists.ceph
age-
> From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of Wido
> den Hollander
> Sent: Tuesday, August 13, 2019 12:51 PM
> To: ceph-users@lists.ceph.com
> Subject: Re: [ceph-users] WAL/DB size
>
>
>
> On 8/13/19 5:54 PM, Hemant Sonawane wrote:
>
.
dhils...@performair.com
www.PerformAir.com
-Original Message-
From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of Wido
den Hollander
Sent: Tuesday, August 13, 2019 12:51 PM
To: ceph-users@lists.ceph.com
Subject: Re: [ceph-users] WAL/DB size
On 8/13/19 5:54 PM
On 8/13/19 5:54 PM, Hemant Sonawane wrote:
> Hi All,
> I have 4 6TB of HDD and 2 450GB SSD and I am going to partition each
> disk to 220GB for rock.db. So my question is does it make sense to use
> wal for my configuration? if yes then what could be the size of it? help
> will be really
Hi All,
I have 4 6TB of HDD and 2 450GB SSD and I am going to partition each disk
to 220GB for rock.db. So my question is does it make sense to use wal for
my configuration? if yes then what could be the size of it? help will be
really appreciated.
--
Thanks and Regards,
Hemant Sonawane
On Fri, Sep 7, 2018 at 3:31 PM, Maged Mokhtar wrote:
> On 2018-09-07 14:36, Alfredo Deza wrote:
>
> On Fri, Sep 7, 2018 at 8:27 AM, Muhammad Junaid
> wrote:
>
> Hi there
>
> Asking the questions as a newbie. May be asked a number of times before by
> many but sorry, it is not clear yet to me.
>
On 2018-09-07 14:36, Alfredo Deza wrote:
> On Fri, Sep 7, 2018 at 8:27 AM, Muhammad Junaid
> wrote:
>
>> Hi there
>>
>> Asking the questions as a newbie. May be asked a number of times before by
>> many but sorry, it is not clear yet to me.
>>
>> 1. The WAL device is just like journaling
I saw above the recommended size for the db partition was 5% of data, but
yet the recommendation is 40GB partitions for 4TB drives. Isn't that closer
to 1%?
On Fri, Sep 7, 2018 at 10:06 AM, Muhammad Junaid
wrote:
> Thanks very much. It is clear very much now. Because we are just in
> planning
Thanks very much. It is clear very much now. Because we are just in
planning stage right now, would you tell me if we use 7200rpm SAS 3-4TB for
OSD's, write speed will be fine with this new scenario? Because it will
apparently writing to slower disks before actual confirmation. (I
understand there
It can get confusing.
There will always be a WAL, and there will always be a metadata DB, for
a bluestore OSD. However, if a separate device is not specified for the
WAL, it is kept in the same device/partition as the DB; in the same way,
if a separate device is not specified for the DB, it is
Thanks again, but sorry again too. I couldn't understand the following.
1. As per docs, blocks.db is used only for bluestore (file system meta data
info etc). It has nothing to do with actual data (for journaling) which
will ultimately written to slower disks.
2. How will actual journaling will
On Fri, Sep 7, 2018 at 9:02 AM, Muhammad Junaid wrote:
> Thanks Alfredo. Just to clear that My configuration has 5 OSD's (7200 rpm
> SAS HDDS) which are slower than the 200G SSD. Thats why I asked for a 10G
> WAL partition for each OSD on the SSD.
>
> Are you asking us to do 40GB * 5 partitions
Hi,
Are you asking us to do 40GB * 5 partitions on SSD just for block.db?
yes. By default ceph deploys block.db and wal.db on the same device if
no separate wal device is specified.
Regards,
Eugen
Zitat von Muhammad Junaid :
Thanks Alfredo. Just to clear that My configuration has 5
Thanks Alfredo. Just to clear that My configuration has 5 OSD's (7200 rpm
SAS HDDS) which are slower than the 200G SSD. Thats why I asked for a 10G
WAL partition for each OSD on the SSD.
Are you asking us to do 40GB * 5 partitions on SSD just for block.db?
On Fri, Sep 7, 2018 at 5:36 PM Alfredo
On Fri, Sep 7, 2018 at 8:27 AM, Muhammad Junaid wrote:
> Hi there
>
> Asking the questions as a newbie. May be asked a number of times before by
> many but sorry, it is not clear yet to me.
>
> 1. The WAL device is just like journaling device used before bluestore. And
> CEPH confirms Write to
Hi there
Asking the questions as a newbie. May be asked a number of times before by
many but sorry, it is not clear yet to me.
1. The WAL device is just like journaling device used before bluestore. And
CEPH confirms Write to client after writing to it (Before actual write to
primary device)?
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