Hello the list,
After participating at the presentation of Bill Moore & Jeff Bonwick, I
started to think about:
``No special hardware ? ZFS loves cheap disks''''
okay it loves it. But _how_ can you achieve a well sized storage (40TB)
with such technologies. I mean, how can you bind physicaly 70 HD in an
zfs pool.
After some thinking, I went with this idea in mind which is shown below
with some ascii :)
+-------+ +-------+ +-------+
|node i1| |node i2| |node i3|
| with | | with | | with |
| 16 HD | | 16 HD | | 16 HD |
+-------+ +-------+ +-------+
\ | /
\ | /
+---------------+
I S C I | jumbo switch | I S C I
i-node +---------------+ i-node
/ \
~~~~~~~~~~~~/~~~~~~~~~~~~\~~~~~~~~~~~~~~~~~~
+-------+ +-------+
|node z0| |node z1|
Z F S | with | | with | Z F S
z-node | 2 HD | | 2 HD | z-node
+-------+ +-------+
~~~~~~~~~~~~\~~~~~~~~~~~~/~~~~~~~~~~~~~~~~~~
\ /
+---------------+
N F S | switch | N F S
n-node +---------------+ n-node
the clients / / | \ the clients
----- / | --oooo ---
/ / | \
+-------+ +-------+ +-------+ +-------+
|node n0| |node n1| |node n2| |node nX|
| with | | with | | with | oooo | with |
| 1 HD | | 1 HD | | 1 HD | | 2 HD |
+-------+ +-------+ +-------+ +-------+
I''ve splitted it like this.
ISCSI space: the one in the top.
-----------
the first from the top.
- It provides the ability to see on z0,z1 hard disks which are
physically mounted on i0,i2,i3
- I have a least three i-node, which will protect me from an unvailable
zpool if one i-node goes down as long as I spread the HD correctly
between the i-node. So I can have a cheap i-node with one power supply.
ZFS space: the middle one
---------
- the z-nodes are here to consolidate the HDs with a zpool
- I will put them into an container so it will be easy to migrate the
zpool from one z-node to an other
- I will create about 6 zpool to be able to do some load balancing
between the z-node.
- there will be a least 2 z-node but I''m open to have more than 2 but
not only one
NFS space: the one in the bottom.
---------
- this will be client which will connect to an z-node
- nothing special here.
OKAY that''s an idea, but then this becomes not so easy to manage. I
have
made some tries and I found iscsi{,t}adm not that cool to use confronted
to what zfs,zpool interfaces provides.
Now the questions:
1) what do you think about such topology
2) Do you have any comment on what I''ve said in the previous line
3) one of the excellent feature of zfs, is that the meta-data kept
inside the HD give the possibility to export and import HD without
worrying about which HD is for which pool. _But_
3.1) In this case (see the ascii draw), I mean using it through iscsi,
we lost this ability to easily find which HD is for. Due to the fact
that iscsi and zfs are two different programs.
3.2) If I use zfs on iscsi HD (IDE), and I create a pool with it and I
decide to export it and plug it directly (without iscsi) to the node.
I''m not able to do an zfs import on the IDE HD. I try to do a
*loopback*
iscsi without success :( . This is sad, because, I was thinking to move
the z-node in the i-node. But I wont be able to do this due to the
behaviour of iscsi.
Ced.
--
Cedric BRINER
Geneva - Switzerland