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Replication between 2 x DL4300 appliances over iSCSI

richard.hamblin
over 8 years ago

Will 2 x DL4300 Rapid Recovery appliances allow replication over an iSCSI network interface rather than using the standard 1Gb Network Interface?

We currently have 2 x 10Gb iSCSI interfaces in each DL4300 being utilized for backup from our Storage but was hoping we can use the same interfaces to replicate to the second DL4300 Replication target.

I have 4 Standard NICs teamed but it only ever hits the 1Gb limit over one of these NICs.

Many thanks in advance

Richard

  • 0 over 8 years ago
    Hi Richard:
    If I understand correctly, you would like to share the nics used for iSCSI with the replication traffic.

    It is possible albeit it is not a recommended setup.

    There are a few things to take into consideration.

    First, is the topology of the connection between the 2 cores. More specifically, is it a local connection or does it connect geographically distinct sites?

    In both cases you need to check what is the end to end sustainable bandwidth. For instance you won't take advantage of your nics capabilities if the two sites are connected by a 50Mb/s link.

    Second, the most important performance factor is given by the IOPS the storage subsystem is able to yield. For instance, as an extreme example, 1Gb/s connection won't help if the storage is located on an USB 2.0 drive.

    Third, it is important to asses the load on your cores. If most of the active time is performed doing internal IOPS intensive operations, for instance rollups, deferred deletes and mountability checks, the overall performance will suffer as well.

    A real life example is the customer who had a very large environment with great specs, and used a 64GB deduplication cache. Since the dedupe cache was flushed on disk every hour and it was located on the C:\ volume (RAID 1), the repository was idle about 30 minutes per hour (and all core activities, including transfers, were paused) due to flushing the cache. Moving the cache on a small SSD RAID array (which was already available in his environment!) improved significantly the overall performance.

    Hope that this helps.
  • 0 over 8 years ago
    Thanks for the reply Tudor,

    Here is some more info about our environment. We have 2 x DL4300 Rapid Recovery appliances (25TB each) which are connected to the same network using 2 x 10Gb Nics (iSCSI) 4 x 1Gb Nics teamed (Lan). We have a 10Gb network backbone between both appliances.

    One appliance does backup directly from our storage area and then replicates this over to the second appliance (currently using the LAN Nics). I was hoping to get the benefit of the 10GB network backbone for replication traffic, but only have the NIC's used for iSCSI connected at that speed. Hence the dual use scenario.

    Would I be better off adding another 10Gb NIC to each appliance and using that for lan traffic?

    I don't really want to be getting into setups that aren't recommended

    thanks again, Richard