Why there is no option for creating 16K blocks. Only available options are 4K and 32K.
Now I am getting a clearer picture.
The reason you see 2x the capacity with 32KB FS block size is because your average file size must be ~16KB or less. With a 32KB FS block size, a 16KB file will consume 1x 32K FS block.
>If I create a block size of 4K in HNAS the size after copying is 150 GB
Yes, this is not unexpected. HNAS has built-in fixed and temporary resiliency that can use up some extra space. On an FS that is 150GB, we will have some fixed utilization for file system structures and temporarily utilization that can vary greatly in size with our file system checkpoints that allow the file system to rollback to previous point in time, by default we keep 128 of these on the file system and they will temporarily use up some space. The fixed utilization is less than .5% on file systems >1TB.
I think it was done to keep things simple, so for small files you choose 4K and for large files choose 32K.
Francisco Salinas orGokula Rangarajan might have a better answer.
Like Biju says, it boils down to keeping things simple.
I agree of keeping it simple, but my issue is i want to migrate my existing file system of size 16K to HNAS, If i select 4K it occupies 2x4K blocks one for data and one for metadata and the same happens with 32K.
But in both the cases the size occupied is more than that of the original size.
What is your existing file system? What is the file size you are copying? What is the capacity reported on the source versus HNAS?
Yes, in HNAS, each file occupies a minimum of 1 FS block for metadata and 1 for data. Even if HNAS supported 16KB blocks, this would not change.
Francisco Salinas Existing FS or the mount point are coming from HP PolyServe cluster and the NFS exports are mounted in a Linux server, The FS size I'm copying is 142 GB. If I create a block size of 4K in HNAS the size after copying is 150 GB and I tried to create the block size with 32K then the size was like 284 GB.
How are you determining the file size? Also, is the file being copied sparse?
Worth checking used capacity rather than total size of the file system.
The total FS size is 150 GB and 142 GB is the used space as per my original nfs export. and whatever the size I have mentioned is the used size only.
I ran df command from linux to check the FS size, and the mount point/nfs export contain only binary files the contents doesn't get changed.
Francisco Salinas thanks for the clarification.
Retrieving data ...