In our HP RAID Controller card we have a cache ratio setting, default is 25% for reads and 75% for writes.mkretzer wrote: We currently use a Fujitsu DX60 S3 Fibre Storage, what do you mean with cache ratio? There is no fixed cache percentage with this as with HP controllers.
We have tried different settings and as transforms (merges) we our main issue, we set it to 50/50.
Here is a test I made to decide where is my next road to go regarding file system (the purpose was not to compare ReFS 4K with ReFS 64K, but ReFS with NTFS in terms of backup window):
- Run the same backup job, on different file systems: ReFS 4K, ReFS 64K, NTFS 32K
- All was ran on the very same hardware (repository configured as CiFS to use fast cloning feature):
- HP DL380 Gen9 with dual CPU Intel E5-2660 v4 2Ghz, 64 GB of RAM, raid 1 SSD for the OS
- Dual 10 Gbit network cards (HP 560FLR) supporting the offloading of SMB v3 (RDMA capabale)
- 2 x DAS HP D3700 with 25 x 1.8TB 12G 10K SAS disks configured as Raid 6 with HP p441 controller
And here are the results (be careful, no missreading, the ReFS 4K was not ran in the exact same conditions, as it took more than 30 minutes, other jobs were started at the same time):
- The job is a single VM, VBK is 420 GB, average VIB size is 20 GB, Forward Incremental with 30 recovery points
- ReFS 4K: 6.5 GB transfered, processing rate 63 MB/s, duration 4h40:20, processing 8min41, Full backup file merge 4h31:01 (as much as 10 jobs running at the same time)
- ReFS 64K: 19.4 GB transfered, processing rate 69 MB/s, duration 28:32, processing 15min08, Full backup file merge 12min51 (only one job at a time, which explains the difference of speed more than the 64K block size)
- NTFS 32K: 40.7 GB transfered, processing rate 62 MB/s, duration 27:32, processing 15min08, Full backup file merge 1min52 (as much as 10 jobs running at the same time) (NTFS must have a mega fast cloning )
So ReFS can be quick, but it really should not be used with too many jobs running in parallel on the same repository. With my hardware, even with ReFS 64K, with 6 jobs running at the same time doing a merge, the file system starts to have a hard time responding even to a simple browse action in windows Explorer.
I had put a lot of hope in ReFS, even worked in TP4 and TP5 on building a on a nano cluster for storage spaces direct (then I found out about the licensing -> datacenter edition only).
But I will be migrating my storage back to NTFS.
The "benefits" of ReFS do not compete with our basic needs in being able to backup all we need to backup every night.