Differences between Isilon and Celerra


Differences between file hosting on the Isilon and the previous file hosting offering based on the Celerra appliance


 Backups

        - File content backup to TSM was included in the cost of hosting on the Celerra.

        - Backup is not included with the Isilon, but we offer snapshot scheduling and an option to replicate the filesystem to UFDC (for a nearline copy) and/or Atlanta (for Disaster Recovery). Additional backups are up to each customer to determine how to best support their service level. While we do have an Enterprise TSM service offering, there's no requirement to utilize it.

 Management was much different for the Celerra than it is for the Isilon. 


       - The Celerra utilized an abstraction called a virtual data mover (VDM) that pretended to be a Windows 2003-era server. This allowed units to manage their filespace through the use of MMC snapins and create shares out of their space at will.

       - The Isilon doesn't have a virtual server abstraction - just shares created out of one huge filespace. At the present time, we don't have a way to delegate rights to units to create or modify shares themselves. We have been told that it's an upcoming feature in a future code release.

Snapshot Support

- The Celerra had a fixed amount of snapshot space available for each filesystem, so schedules and retention had to sometimes be curbed to fit within the space on filesystems that had a lot of daily changes.

- On the Isilon, snapshot use is part of your filespace quota, so schedules and retention periods can be set for whatever your departmetn needs are.

Deduplication

- The Celerra had built-in deduplication and compression to optimize the amount of space utilized.

- The Isilon does not offer deduplication as of yet. It is a feature that will be released in the future, however.


  Quota Support

       - The Celerra supported tree directory quotas to limit space allocated to a directory structure, but didn't support nested tree quotas, and configuring/manipulating them had to be done administratively by CNS. The Celerra did support User quotas managed through the Windows User quota plugin available in Properties for the file share.

       - The Isilon supports directory quotas, including nested directory quotas, group quotas, and user based quotas. At the present time, we're unable to expose the quota management interface to our customers, so we will need to add them on your behalf, but we hope that the upcoming code revision will allow us to do so.


  Network ACL support to isolate hosted filesystems

        - The Celerra's virtual data mover had a dedicated ip address that can be used to isolate the filesystem completely from other filesystems.
        - The Isilon supports ACL restrictions if they are requested. By default, we use a general pool of addresses that has ACLs that allow CIFS traffic from campus networks. If you have PCI, HIPPA, FERPA, or other data that requires network isolation, please include that information in your request so a special address pool can be created for your needs.

        note: NTFS and Share permissions are required to access any share hosted from the Isilon. Someone missing those permissions will not even see a "hidden" share listed under the current firmware revision, but we wanted to be sure to disclose this to units who have an audit requirement that demands more aggressive isolation.

  Cost

        - Disk space from the Isilon is around 25% of the cost that it was from the Celerra.

 Replication options


         - We didn't have options to replicate disk content from one Celerra appliance to another

         - The Isilon has options to provide file replication (asynchronously on a 30 min schedule by default) between the SSRB, ECDC, and Atlanta nodes (please see https://open-systems.ufl.edu/hosting for pricing options).

            note: Please note that Atlanta replication option is being offered for offsite backup only. The filesystem will not be accessible to clients from that location in the same manner that a replicated copy would be from SSRB/CSE.

Short File Name Support

  - The Celerra supported short file name support for backwards compatibility with Microsoft's proprietary CIFS extensions.

  - The Isilon does not provide short file namespace support. 

We have run into one practical effect of not having short filename space support so far. Windows clients have a built-in 260 character path limit (including filename) for any filesystem.  When a Windows client hits the 260 character limit, it will attempt to convert the path to use short filename space in order to allow it to traverse farther.  This means that on an Isilon share, when a Windows client reaches a directory that contains a file or folder that will exceed the 260 character path limit, it will stop at the current directory. 

Mac and Linux clients do not restrict file access to a 260 character path on a CIFS share.  The practical effect of this means that in a mixed computing environment, it is possible for a Mac or Linux client to create content on an Isilon share that is too deep for a Windows client to access.

If this poses an issue for you, please contact us. We intend to make an alternative CIFS share service available before the Celerra hardware goes out of maintenance. Pricing has not set for it yet, but it will be more expensive than the Isilon equivalent.

Reporting

The Celerra did not lend itself well to automated reporting emails and scripting. The Isilon does - we send out weekly reports to those listed as technical contacts for the account showing current disk use (including snapshot sizes).

Speed

The Celerra's service was provided by a connection to one of the 4 - 1GB network interfaces. The Isilon's service is via a connection to 1 of 6 - 10gb network interfaces.  This will scale out further when additional nodes are added in the future.