NDMP Backup Issue with Celerra

Question

In our VNX5700 setup we have 4 Data Mover(DM) out of which 2 are in use(active-passive). It is known to us that each DM is capable of hosting 256 TB of File server data & a maximum of 512 TB File server data could be hosted.

Currently we only have around 25 TB of production File server data configured on 2 VDM's & 2 CIFS servers.

However, there is a known limitation of each DM from NDMP backup point of view that it supports 8 concurrent sessions.

Due to this known limitation with Celerra, we are having troubles fitting the NDMP FUll backups within the backup window. It takes approximate 20 Hrs to backup 1 TB of NDMP data eventhough we have a 10 Gig Network.

We have following questions related to this issue:-

1. If our File server data grows upto 256 TB, how are we supposed to fit our backups in the scheduled window with this limitation & above backup speed statistics without activating another Data Mover, which we see is a waste of storage efficiency?

2. To overcome this limitation, we are would be releasing our another DM (server_4 & 5) that are currently not active in similar configuration to allow additional 8 concurrent NDMP sessions.Will just activation of server_4 allow to backup 16 FS at one go {that are hosted currently on server_2 & none on server_4} without hosting the File systems OR we need to move these File systems to server_4?

3. IF we Activate Server_4 & Migrate one of our (CIFS server) from server_2 to server_4 instead, Does it have any impact/downtime?

Does FS data needs to be migrated seperately after migrating CIFS server?

4. Is there any configuration change that we could do from network side to increase the current NDMP backup speed of approx. 50 GB/hr?

Appreciate your expert advice, as we need to be making a decision soon.

EUtRWBdG1A12566 · Answer

Hello Guys,

My basic question is that if a single Data Mover boasts of supporting 256 TB of File server data & we are not able to backup this huge amount of data due to limitation of 8 Concurrent session via NDMP, what is the use of it supporting this amount of data?

dynamox · Answer

if you have that much data you might need to look at alternative backup/DR strategy. Maybe it's another VNX at DR facility that you replicate to with combination of local and remote snapshots. Maybe you need to consider another backup tool like Avamar that beside the first backup is 'incremental forever'.

Rainer_EMC · Answer

You would be surprised how many customer dont do a classical tape backup any longer and instead replicate to a second VNX

VivekSoni · Answer

https://support.emc.com/docu7291_Configuring-NDMP-Backups-on-Celerra.pdf?language=en_US

Hello,

NDMP is a very heavy protocol on the DM. Running just 1 stream can take a lot of CPU. Try to check your speed with SNAPSURE feature enabled (on the TPA/DM) because it helps big time.

Second big question is how are you running/taking backups ? Is it a 2 way NDMP backup or 3 way backup or over the existing LAN.

Thirdly, what is it that you are backing up. If you have one chunk of data (eg: 20 TB) will get backed up faster than having 10 chunks totaling to 20 TB.

You should also check the media you are backing the data to. Tapes or Disks. Different devices/media have different performance.

These are environmental factors that need to be considered during implementation of the technology. If you really have a lot of data that needs backing up and you are not able to complete it with the existing environment, as mentioned above, you should quickly start thinking of other Backup/DR solutions like Replication (File/Block - MirrorView/RP).

For more clarity on NDMP protocol and its functionality, you can refer (recommended) to the NDMP doc (link posted on top).

VNX

NDMP Backup Issue with Celerra

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