10. Source
RADOS (Reliable Autonomic Distributed Object Store)
A reliable, autonomic, distributed object store comprised of self-healing, self-managing,
intelligent storage nodes
LIBRADOS
A library allowing
apps to directly
access RADOS,
with support for C,
C++, Java, Python,
Ruby, and PHP.
RADOSGW (RGW)
(Object gateway)
A bucket-based
REST gateway,
compatible with S3
and Swift.
RBD
(Raw Block Device)
A reliable and fully-
distributed block
device, with a Linux
kernel client and a
QEMU/KVM driver
CEPH FS
(File System)
A POSIX-compilant
distributed
fi
le system
HOST/VM Client
APP
APP
ISCSI Target
HTTP NAS (NFS, CIFS)
SAN (iSCSI)
libRBD libCEPHFS
ISCSI GW
CEPH
block File
Object
17. Comparison IDE/ATA vs SCSI
Feature IDE/ATA SCSI
Connectivity Market Internal Storage Internal and External Storage
Speed (MB/sec) 100/133/150 320
Hot Pluggable No Yes
Expandability Easier to set up
Very good but very expensive to
set up
Cost/Performance Good High cost/Fast transfer speed
18. SAS (Serial Attached SCSI)
• SAS (Serial Attached SCSI)
用
來取代 Parallel SCSI (SCSI-3)
• SAS 同樣使
用
SCSI command set (protocol)
• SATA介
面
的硬碟可以插到SAS的插槽,但 SAS介
面
的硬碟不能插到 SATA 插槽
19. iSCSI (是一種通訊協定,ex. 台語)
•
又
稱為 IP-SAN
• 透過 TCP/IP (網路) 與 SCSI command set (通訊協定)
• Cable 就是網路線,但最好有搭配專屬的網路卡,不要跟 LAN 打架,會吃
一
些 CPU (IP header)
• 連接裝置數沒有上限 (SCSI-3 的上限是15台)
• 對主機
而
言
,看起來就像 local attached disk
• 主要競爭對
手
:光纖通道 (
fi
ber channel)
• 也是
一
種 protocol,傳遞媒介可以是光纖 (optical),也可以是銅線,也可以跑 SCSI
command,包在 FC frame 中,主流是16GFC,
目
前已經有32GFC的交換機產品。
30. SAN vs NAS
SAN NAS
Block level data access File level data access
Fiber channel is the primary media used
with SAN (單獨的
高
速通道). (也可以跑在網
路上,
fi
bre channel over Ethernet (FCoE),
或使
用
iSCSI protocol)
Ethernet is the primary media used use
NAS
SCSI is the main I/O protocol
NFS/CIFS is used as the main I/O protocol
in NAS
SAN storage appears to the computer as its
own storage
NAS appears as a shared folder to the
computer
It can have excellent speeds and
performance when used with
fi
ber channel
media
It can sometimes worsen the performances,
it the network is being used for other things
as well(which normally is the case)