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September 3rd, 2021 01:00
ME4 volume allocated space different on replication partners
Hallo community,
I'm Andreas and as Dell ProSupport did not find an answer so far I will give it a shot here:
I am running two ME4 in replication mode, which is working generally great. But what I discovered is that space allocated on the source system massively differs from space allocated of the same volume on the replication partner/destination (which is absolutely identical system).
First I was thinking it has to do with snapshot space consumed, but tech support told me those (invisible) replication snapshots count against pool space and not volume allocated space (which makes sense):
Source System -> See volume SUMMIT_SQL_1:
Destination System:
Can anyone please throw some light on this matter.
Thanks a lot in advance,
Andreas from Germany
DiegoLopez
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2.7K Posts
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September 28th, 2021 07:00
Hello @Andreas Schmitz,
Sorry for the late reply. Did you got any news from the case you had open with Dell Support? Does the problem persist?
Regards.
Andreas Schmitz
2 Posts
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September 29th, 2021 00:00
Hello Diego,
I am in contact with Dell-Support, but they are kinda stuck. I have update all firmware to latest version on both storages. I have removed the replication of groups and have configured one replication for each volume. This enabled following menu (as described in the manual):
They told me to set Secondary Volume Snapshot Retention to "1". Which I did, and now - wonder, wonder - I have exactly one (visible) Snapshot on the Secondary Storage (which is not what I wanted, nor is it what I have asked). The "replication snapshots" are still invisible, which brings me to 3 snapshots in total:
My initial problem still exists, the volume on the secondary volume is growing larger overtime while the volume on the primary storage is way smaller (primary: 737 GB vs. secondary: 960 GB the very second).
The sent me a weird "copy and pasted" text raving around SNAPSHOTS, but no word about VOLUME-sitzes. At least nothing I understand or did not know.
What I want is simple:
1. I want no visible, manual or automatic snapshots (so NO secondary volumen snapshot history).
2. I want the secondary volume to be a 1:1 copy of the primary volume (with same sizes):
- so why is the secondary VOLUME way larger than the primary VOLUME?
- I guess this is not explainable with different block sizes oder different page sizes?
- keep in mind that primary and secondary storage hardware is identical!
3. I want a fully mirrored (not real-time mirror though - else I would have gone for a compellent) storage which I can use as main storage in case of total failure/loss of the primary storage. Nothing else.
If the volume size of a replicated volume is knowingly meant to be larger than the original volume where is the sense of having a replicated storage hardware? This would mean over time the secondary hardware needs to be exessively upgraded with disks and additional shelves?
I would be great if you could pass this on to one developer or engineer who can elaborate or contact me directly. So far I am stuck with german support rep and 3rd level support rep. What I need is a solution or at least answer from one person who knows the design of the whole system.
Thank you ever so much in advance,
Best regards,
Andreas