IceBoosteR
Guru
- Joined
- Sep 27, 2016
- Messages
- 503
Hello out there,
I got some problems and I think this is related to the deduplication implementation of FreeNAS. But before I open a Bug for that, I want to hear your opinion.
First of all, I am aware of anything I am doing, and that deduplication can have its risks and some performance decrease. So far, so good. But in my cases, this is hitting performance too much.
I got 2 systems with different hardware and FN versions, where I can reproduce the problem:
1st Server:
Xeon E3-1225v3
24GB RAM
4x4TB WD Red
FreeNAS 9.10.2-U6
2nd Server:
2x Xeon L5630
56GB RAM
14x450GB HDD
FreeNAS 11.0-U2
So I got deduplication enabled on some datasets. I saved some gigabytes of storage and dedup table is small ~1GB in RAM max.
When I am copying data to a dataset when dedup is ON or VERIFY, the connection drops every minute, sometimes every 30 seconds, sometimes every 2 minutes. Depends on the data transferred. When the connection drops, I mean that NO read or write happen to that dataset at this specific moment, and Windows shows transferspeeds of 0kb/s instead of 100+MB/s. For 15-30 seconds this state is hold and after that time, the copying resumes (photo attached).
On the other hand, I got a ZVOL vor ESXi datastores. I also enable dedup here for saving storage on the VMs. But when heavy write is done, sometimes the VMs freezes and shows me iSCSI error, that they are waiting for the connection. This can also be found in the log of FN, that the iSCSI has I/O problems.
This is not a CPU or RAM problem, also I think the disks are not the bottleneck has normal transfers has always 100+MB/s so I assume it's the deduplication or the implementaion of this.
Now don't tell me that I should not use dedup, but any helpful comment would be appreciate - because the workaround is to disable dedup ;)
I got some problems and I think this is related to the deduplication implementation of FreeNAS. But before I open a Bug for that, I want to hear your opinion.
First of all, I am aware of anything I am doing, and that deduplication can have its risks and some performance decrease. So far, so good. But in my cases, this is hitting performance too much.
I got 2 systems with different hardware and FN versions, where I can reproduce the problem:
1st Server:
Xeon E3-1225v3
24GB RAM
4x4TB WD Red
FreeNAS 9.10.2-U6
2nd Server:
2x Xeon L5630
56GB RAM
14x450GB HDD
FreeNAS 11.0-U2
So I got deduplication enabled on some datasets. I saved some gigabytes of storage and dedup table is small ~1GB in RAM max.
When I am copying data to a dataset when dedup is ON or VERIFY, the connection drops every minute, sometimes every 30 seconds, sometimes every 2 minutes. Depends on the data transferred. When the connection drops, I mean that NO read or write happen to that dataset at this specific moment, and Windows shows transferspeeds of 0kb/s instead of 100+MB/s. For 15-30 seconds this state is hold and after that time, the copying resumes (photo attached).
On the other hand, I got a ZVOL vor ESXi datastores. I also enable dedup here for saving storage on the VMs. But when heavy write is done, sometimes the VMs freezes and shows me iSCSI error, that they are waiting for the connection. This can also be found in the log of FN, that the iSCSI has I/O problems.
This is not a CPU or RAM problem, also I think the disks are not the bottleneck has normal transfers has always 100+MB/s so I assume it's the deduplication or the implementaion of this.
Now don't tell me that I should not use dedup, but any helpful comment would be appreciate - because the workaround is to disable dedup ;)
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