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Notes on using file gateways

Last Updated: Jul 01, 2019

1.We recommend that you do not frequently copy large files to NFS or SMB shares. Files are uploaded to shares through multipart uploads. If you interrupt uploads of large files, file fragments will be generated in OSS buckets. These fragments affect capacity statistics of OSS buckets, and cause the OSS bucket capacity to be slightly larger than the total file capacity. These fragments will be automatically cleared by the background garbage collection mechanism of OSS.

2.The cache capacity of each share is calculated based on the following formula:

Recommended local cache capacity = (Application bandwidth [Mbit/s] - Bandwidth of the gateway (Mbit/s) × Time duration of the write operation (seconds) × 1.2

If you want the local cache disk to have a higher I/O throughput, calculate the total amount of hot data. Compare the total amount of hot data with the largest recommended local cache capacity, and set the capacity of the local cache disk to whichever is greater.

3.If you need to write large files to the file system, the size of each file must be smaller than 30% of the cache disk capacity. You cannot write multiple large files at the same time. Otherwise, the cache disk space will be exhausted.

4.The maximum file size supported by version 1.0.30 and earlier is 122 GB. The maximum file size supported by version 1.0.31 and later is 1.2 TB. Since 1.0.38, CSG will support maximum 30TB file uploaded to OSS. When uploading large file(> 2TB), it preferred the network connection to OSS should be higher than 500Mb/s. Otherwise it will be easy to hit timeout error.

5.Folders and files cannot have the same name due to the limits of the Linux file system.

6.Version 1.0.31 and later support sparse files. Earlier versions do not support sparse files. If the gateway version is earlier than 1.0.31, you will fail to upload sparse files to the gateway. Run the following command to convert the sparse files to the non-sparse state first:

dd if=<sparse file name> of=<sparse file name> conv=notrunc bs=1M

Currently supported sparse files size requirements do not exceed the size of the available cache disk.

7.The Alibaba Cloud CSG console does not support the following operations for version 1.0.35:

A. Create or delete an SMB user.

B. Create or delete the read/write client list.

C. Use AD or LDAP

You need to perform these operations in the gateway console, or upgrade the gateway to version 1.0.36 in the Alibaba Cloud CSG console.