Just switched to cloud storage, combined with recent learning, the following summarizes some of the differences between traditional SAN and distributed storage, mainly
Personal opinion, welcome to Paizhuan.
0. Differences in user experience
traditional SAN |
Distributed storage |
|
Operation interface |
Remotely link to the storage server port over the network, which provides a graphical interface |
Users are generally invisible, only after-sales or technical personnel can control |
Access control |
Implement ACL through backend target , user, and user group |
None, background management |
Volume operations |
Support volume / clone / snapshot creation, modification, deletion, online and offline |
Yes, backend CLI and frontend interface |
Common applications |
VDI virtual desktop, data center in small computer room |
Virtual machine, easy to go online |
Applicable scene |
Applications requiring high reliability, stability and performance |
Cost-sensitive scenarios |
System monitoring |
Comprehensive, system BMC , PSU , CPU , MEM , storage status and capacity |
Very few, only whether there is an IO error, whether the volume is normal, etc. |
system alarm |
Rich, covering software and hardware, rich in layers, visible to users |
Fewer, generally invisible to users |
1. The difference between external interfaces
traditional SAN |
Distributed storage |
|
iSCSI |
support |
can support |
Fiber Channel |
support |
not support |
FCoE |
support |
not support |
RDMA |
can support |
support |
2. Differences in TCO
Traditional SAN / NAS |
Distributed storage |
|
storage resources |
Low |
very low |
computing resources |
high |
Low |
3. System Features
traditional SAN |
Distributed storage |
|
Available rows |
Realize through dual control, remote replication, same-city / remote disaster recovery |
Implemented by spreading multiple copies to different fault domains |
reliability |
Realized by RAID , erasure code, check code |
without |
serviceability |
Provides functions for automatic diagnosis, automatic alarm generation and elimination |
Generate alerts |
Advanced Features |
Compression, deduplication, encryption, cloud service |
encryption |
Scalability |
Scale up (hardware upgrade) + JBOD |
horizontal expansion |
Applicable scene |
Applications requiring high reliability, stability and performance |
Scenarios that are more sensitive to costs or require rapid business rollout |
4. The difference between architecture and implementation
traditional SAN |
Distributed storage |
|
Fail-over |
Dual control takes over through heartbeat detection |
Implemented through PaxOS -like |
storage unit |
Bands |
replication group |
logical address to physical address mapping |
Utilize traditional index blocks and block pointers |
Hash |
global space management |
Bitmap or linked list |
Hash based |
5. Areas for improvement
Traditional users are accustomed to the interface provided by SAN / NAS . If cloud storage manufacturers can integrate the existing SAN interface of customers or provide a similar interface, it will greatly facilitate users;
At present , SAN can go to the cloud, so can cloud storage manufacturers provide interfaces to implement the cloud, and manage the storage space based on the SAN in a unified manner, so that the commonly used data is still stored in the SAN , which can not only benefit the old but also expand the capacity.