Re: [ceph-users] Ceph Luminous RocksDB vs WalDB?

2018-06-28 Thread Igor Fedotov 
The idea is to avoid separate WAL partition - it doesn't make sense for 
single NVMe device - just compicates things.


And if you don't specify WAL explicitly it's co-exist with DB.

Hence I vote for the second option :)


On 6/29/2018 12:07 AM, Kai Wagner wrote:


I'm also not 100% sure but I think that the first one is the right way 
to go. The second command only specifies the db partition but no 
dedicated WAL partition. The first one should do the trick.



On 28.06.2018 22:58, Igor Fedotov wrote:


I think the second variant is what you need. But I'm not the guru in 
ceph-deploy so there might be some nuances there...


Anyway the general idea is to have just a single NVME partition (for 
both WAL and DB) per OSD.


Thanks,

Igor


On 6/27/2018 11:28 PM, Pardhiv Karri wrote:

Thank you Igor for the response.

So do I need to use this,

ceph-deploy osd create --debug --bluestore --data /dev/sdb 
--block-wal /dev/nvme0n1p1 --block-db /dev/nvme0n1p2 cephdatahost1


or

ceph-deploy osd create --debug --bluestore --data /dev/sdb 
--block-db /dev/nvme0n1p2 cephdatahost1


where /dev/sdb is ssd disk for osd
/dev/nvmen0n1p1 is 10G partition
/dev/nvme0n1p2 is 25G partition


Thanks,
Pardhiv K

On Wed, Jun 27, 2018 at 9:08 AM Igor Fedotov > wrote:


Hi Pardhiv,

there is no WalDB in Ceph.

It's WAL (Write Ahead Log) that is a way to ensure write safety
in RocksDB. In other words - that's just a RocksDB subsystem
which can use separate volume though.

In general For BlueStore/BlueFS one can either allocate separate
volumes for WAL and DB or have them on the same volume. The
latter is the common option.

The separated layout makes sense when you have tiny but
super-fast device (for WAL) and less effective (but still fast)
larger drive for DB. Not to mention the third one for user data

E.g. HDD (user data) + SDD (DB) + NVME  (WAL) is such a layout.


So for you case IMO it's optimal to have merged WAL+DB at NVME
and data at SSD. Hence no need for separate WAL volume.


Regards,

Igor


On 6/26/2018 10:22 PM, Pardhiv Karri wrote:

Hi,

I am playing with Ceph Luminous and getting confused
information around usage of WalDB vs RocksDB.

I have 2TB NVMe drive which I want to use for Wal/Rocks DB and
have 5 2TB SSD's for OSD.
I am planning to create 5 30GB partitions for RocksDB on NVMe
drive, do I need to create partitions of WalDB also on NVMe
drive or does RocksDB does same work as WalDB plus having
metadata on it?

So my question is do I really need to use WalDB along with
RocksDB or having RocksDB only is fine?

Thanks,
Pardhiv K





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Re: [ceph-users] Ceph Luminous RocksDB vs WalDB?

2018-06-28 Thread Kai Wagner 
On 28.06.2018 23:25, Eric Jackson wrote:
> Recently, I learned that this is not necessary when both are on the same 
> device.  The wal for the Bluestore OSD will use the db device when set to 0.
That's good to know. Thanks for the input on this Eric.

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Re: [ceph-users] Ceph Luminous RocksDB vs WalDB?

2018-06-28 Thread Eric Jackson 
I'm going to hope that Igor is correct since I have a PR for DeepSea to change 
this exact behavior.

With respect to ceph-deploy, if you specify --block-wal, your OSD will have a 
block.wal symlink.  Likewise, --block-db will give you a block.db symlink.

If you have both on the command line, you will get both.  That does work, but 
this also means twice the partitions to manage on a shared device.  We have 
been doing Bluestore this way in DeepSea since we started supporting 
Bluestore.

Recently, I learned that this is not necessary when both are on the same 
device.  The wal for the Bluestore OSD will use the db device when set to 0.  
I will soon verify that also means when the block.wal is absent.  

Eric

On Thursday, June 28, 2018 5:07:25 PM EDT Kai Wagner wrote:
> I'm also not 100% sure but I think that the first one is the right way
> to go. The second command only specifies the db partition but no
> dedicated WAL partition. The first one should do the trick.
> 
> On 28.06.2018 22:58, Igor Fedotov wrote:
> > I think the second variant is what you need. But I'm not the guru in
> > ceph-deploy so there might be some nuances there...
> > 
> > Anyway the general idea is to have just a single NVME partition (for
> > both WAL and DB) per OSD.
> > 
> > Thanks,
> > 
> > Igor
> > 
> > On 6/27/2018 11:28 PM, Pardhiv Karri wrote:
> >> Thank you Igor for the response.
> >> 
> >> So do I need to use this,
> >> 
> >> ceph-deploy osd create --debug --bluestore --data /dev/sdb
> >> --block-wal /dev/nvme0n1p1 --block-db /dev/nvme0n1p2 cephdatahost1
> >> 
> >> or 
> >> 
> >> ceph-deploy osd create --debug --bluestore --data /dev/sdb --block-db
> >> /dev/nvme0n1p2 cephdatahost1
> >> 
> >> where /dev/sdb is ssd disk for osd
> >> /dev/nvmen0n1p1 is 10G partition
> >> /dev/nvme0n1p2 is 25G partition
> >> 
> >> 
> >> Thanks,
> >> Pardhiv K
> >> 
> >> On Wed, Jun 27, 2018 at 9:08 AM Igor Fedotov  >> 
> >> > wrote:
> >> Hi Pardhiv,
> >> 
> >> there is no WalDB in Ceph.
> >> 
> >> It's WAL (Write Ahead Log) that is a way to ensure write safety
> >> in RocksDB. In other words - that's just a RocksDB subsystem
> >> which can use separate volume though.
> >> 
> >> In general For BlueStore/BlueFS one can either allocate separate
> >> volumes for WAL and DB or have them on the same volume. The
> >> latter is the common option.
> >> 
> >> The separated layout makes sense when you have tiny but
> >> super-fast device (for WAL) and less effective (but still fast)
> >> larger drive for DB. Not to mention the third one for user data
> >> 
> >> E.g. HDD (user data) + SDD (DB) + NVME  (WAL) is such a layout.
> >> 
> >> 
> >> So for you case IMO it's optimal to have merged WAL+DB at NVME
> >> and data at SSD. Hence no need for separate WAL volume.
> >> 
> >> 
> >> Regards,
> >> 
> >> Igor
> >> 
> >> On 6/26/2018 10:22 PM, Pardhiv Karri wrote:
> >>> Hi,
> >>> 
> >>> I am playing with Ceph Luminous and getting confused information
> >>> around usage of WalDB vs RocksDB.
> >>> 
> >>> I have 2TB NVMe drive which I want to use for Wal/Rocks DB and
> >>> have 5 2TB SSD's for OSD. 
> >>> I am planning to create 5 30GB partitions for RocksDB on NVMe
> >>> drive, do I need to create partitions of WalDB also on NVMe
> >>> drive or does RocksDB does same work as WalDB plus having
> >>> metadata on it? 
> >>> 
> >>> So my question is do I really need to use WalDB along with
> >>> RocksDB or having RocksDB only is fine?
> >>> 
> >>> Thanks,
> >>> Pardhiv K
> >>> 
> >>> 
> >>> 
> >>> 
> >>> 
> >>> ___
> >>> ceph-users mailing list
> >>> ceph-users@lists.ceph.com 
> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >> 
> >> ___
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Re: [ceph-users] Ceph Luminous RocksDB vs WalDB?

2018-06-28 Thread Kai Wagner 
I'm also not 100% sure but I think that the first one is the right way
to go. The second command only specifies the db partition but no
dedicated WAL partition. The first one should do the trick.


On 28.06.2018 22:58, Igor Fedotov wrote:
>
> I think the second variant is what you need. But I'm not the guru in
> ceph-deploy so there might be some nuances there...
>
> Anyway the general idea is to have just a single NVME partition (for
> both WAL and DB) per OSD.
>
> Thanks,
>
> Igor
>
>
> On 6/27/2018 11:28 PM, Pardhiv Karri wrote:
>> Thank you Igor for the response.
>>
>> So do I need to use this,
>>
>> ceph-deploy osd create --debug --bluestore --data /dev/sdb
>> --block-wal /dev/nvme0n1p1 --block-db /dev/nvme0n1p2 cephdatahost1
>>
>> or 
>>
>> ceph-deploy osd create --debug --bluestore --data /dev/sdb --block-db
>> /dev/nvme0n1p2 cephdatahost1
>>
>> where /dev/sdb is ssd disk for osd
>> /dev/nvmen0n1p1 is 10G partition
>> /dev/nvme0n1p2 is 25G partition
>>
>>
>> Thanks,
>> Pardhiv K
>>
>> On Wed, Jun 27, 2018 at 9:08 AM Igor Fedotov > > wrote:
>>
>> Hi Pardhiv,
>>
>> there is no WalDB in Ceph.
>>
>> It's WAL (Write Ahead Log) that is a way to ensure write safety
>> in RocksDB. In other words - that's just a RocksDB subsystem
>> which can use separate volume though.
>>
>> In general For BlueStore/BlueFS one can either allocate separate
>> volumes for WAL and DB or have them on the same volume. The
>> latter is the common option.
>>
>> The separated layout makes sense when you have tiny but
>> super-fast device (for WAL) and less effective (but still fast)
>> larger drive for DB. Not to mention the third one for user data
>>
>> E.g. HDD (user data) + SDD (DB) + NVME  (WAL) is such a layout.
>>
>>
>> So for you case IMO it's optimal to have merged WAL+DB at NVME
>> and data at SSD. Hence no need for separate WAL volume.
>>
>>
>> Regards,
>>
>> Igor
>>
>>
>> On 6/26/2018 10:22 PM, Pardhiv Karri wrote:
>>> Hi,
>>>
>>> I am playing with Ceph Luminous and getting confused information
>>> around usage of WalDB vs RocksDB.
>>>
>>> I have 2TB NVMe drive which I want to use for Wal/Rocks DB and
>>> have 5 2TB SSD's for OSD. 
>>> I am planning to create 5 30GB partitions for RocksDB on NVMe
>>> drive, do I need to create partitions of WalDB also on NVMe
>>> drive or does RocksDB does same work as WalDB plus having
>>> metadata on it? 
>>>
>>> So my question is do I really need to use WalDB along with
>>> RocksDB or having RocksDB only is fine?
>>>
>>> Thanks,
>>> Pardhiv K
>>>
>>>
>>>
>>>
>>>
>>> ___
>>> ceph-users mailing list
>>> ceph-users@lists.ceph.com 
>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>
>> ___
>> ceph-users mailing list
>> ceph-users@lists.ceph.com 
>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>
>>
>>
>> -- 
>> *Pardhiv Karri*
>> "Rise and Rise again untilLAMBSbecome LIONS" 
>>
>>
>
>
>
> ___
> ceph-users mailing list
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Re: [ceph-users] Ceph Luminous RocksDB vs WalDB?

2018-06-28 Thread Igor Fedotov 
I think the second variant is what you need. But I'm not the guru in 
ceph-deploy so there might be some nuances there...


Anyway the general idea is to have just a single NVME partition (for 
both WAL and DB) per OSD.


Thanks,

Igor


On 6/27/2018 11:28 PM, Pardhiv Karri wrote:

Thank you Igor for the response.

So do I need to use this,

ceph-deploy osd create --debug --bluestore --data /dev/sdb --block-wal 
/dev/nvme0n1p1 --block-db /dev/nvme0n1p2 cephdatahost1


or

ceph-deploy osd create --debug --bluestore --data /dev/sdb --block-db 
/dev/nvme0n1p2 cephdatahost1


where /dev/sdb is ssd disk for osd
/dev/nvmen0n1p1 is 10G partition
/dev/nvme0n1p2 is 25G partition


Thanks,
Pardhiv K

On Wed, Jun 27, 2018 at 9:08 AM Igor Fedotov > wrote:


Hi Pardhiv,

there is no WalDB in Ceph.

It's WAL (Write Ahead Log) that is a way to ensure write safety in
RocksDB. In other words - that's just a RocksDB subsystem which
can use separate volume though.

In general For BlueStore/BlueFS one can either allocate separate
volumes for WAL and DB or have them on the same volume. The latter
is the common option.

The separated layout makes sense when you have tiny but super-fast
device (for WAL) and less effective (but still fast) larger drive
for DB. Not to mention the third one for user data

E.g. HDD (user data) + SDD (DB) + NVME  (WAL) is such a layout.


So for you case IMO it's optimal to have merged WAL+DB at NVME and
data at SSD. Hence no need for separate WAL volume.


Regards,

Igor


On 6/26/2018 10:22 PM, Pardhiv Karri wrote:

Hi,

I am playing with Ceph Luminous and getting confused information
around usage of WalDB vs RocksDB.

I have 2TB NVMe drive which I want to use for Wal/Rocks DB and
have 5 2TB SSD's for OSD.
I am planning to create 5 30GB partitions for RocksDB on NVMe
drive, do I need to create partitions of WalDB also on NVMe drive
or does RocksDB does same work as WalDB plus having metadata on it?

So my question is do I really need to use WalDB along with
RocksDB or having RocksDB only is fine?

Thanks,
Pardhiv K





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Re: [ceph-users] Ceph Luminous RocksDB vs WalDB?

2018-06-27 Thread Igor Fedotov 

Hi Pardhiv,

there is no WalDB in Ceph.

It's WAL (Write Ahead Log) that is a way to ensure write safety in 
RocksDB. In other words - that's just a RocksDB subsystem which can use 
separate volume though.


In general For BlueStore/BlueFS one can either allocate separate volumes 
for WAL and DB or have them on the same volume. The latter is the common 
option.


The separated layout makes sense when you have tiny but super-fast 
device (for WAL) and less effective (but still fast) larger drive for 
DB. Not to mention the third one for user data


E.g. HDD (user data) + SDD (DB) + NVME  (WAL) is such a layout.


So for you case IMO it's optimal to have merged WAL+DB at NVME and data 
at SSD. Hence no need for separate WAL volume.



Regards,

Igor


On 6/26/2018 10:22 PM, Pardhiv Karri wrote:

Hi,

I am playing with Ceph Luminous and getting confused information 
around usage of WalDB vs RocksDB.


I have 2TB NVMe drive which I want to use for Wal/Rocks DB and have 5 
2TB SSD's for OSD.
I am planning to create 5 30GB partitions for RocksDB on NVMe drive, 
do I need to create partitions of WalDB also on NVMe drive or does 
RocksDB does same work as WalDB plus having metadata on it?


So my question is do I really need to use WalDB along with RocksDB or 
having RocksDB only is fine?


Thanks,
Pardhiv K





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