Exadata -- About Extended (XT) Storage Servers

In Exadata X8 environment, we have an option to have Exadata Extended(XT) Storage Servers /Cells. It is a new feature for Exadata X8 actually..

It is important to mention that, we must have Exadata X4 or newer to use this Exadata XT cells for extending our storage capacity with a lower cost.

With this XT storage option, Oracle offers a lower cost storage which can be used for infrequently accessed, older, or regulatory data. (such as Historical data, Images, BLOBs, contracts, local backups and other large table-based objects compliance and regulatory data)

To provide a lower cost , Oracle made some decreases mostly in computational resources side of this Cell type. Well.. Flash is not included. Smart scan is optionally included. That is, the software license is optional . (we must purchase it to use Smart Scan on these XT cells)

It is good to know that HCC is included. Imaging, upgrading is the same.. (In the latest Exadata environments (X7 or X8), we generally use ILOM for mounting the images and booting from there).. In our experience, Pxe boot is a little complicated (we had some struggles lately) in the new Exadata deployments.

Okay let's see what we have with these XT Storage servers...

1 XT Storage Server has;

12 x14TB 7200 RPM SAS disks (total 168GB raw disk capacity)
1 x 16core Intel Xeon 5218 processor.
96 GB Memory
No Flash
2 x QDR (40GBB) infiniband port.
1 x ILOM Port.

When we compare it with HC or EF, we can say that the memory size and cpu power of XT is half of HC or EF storage cells. We don' have Nvme flash in XT, but still we have a quite big enough storage capacity.

On the other hand; XT seems more than 2 times chepar than EF or EC storage cells. So it is logical to use it in certain situations.

In these days, we are increasing the storage capacity of our Exadata customers and we started to deal with these Exadata XT storages... So I will finish this post by giving you some info about the implementation as well. Actually the restrictions regarding these XT storages..

That is;

DATA/RECO diskgroups are not allowed on XT storage servers
A cluster cannot consist of just XT servers
A diskgroup must include all cells of a celltype (XT, EF or HC)
A diskgroup cannot contain a mixture of celltype (XT, EF or HC)