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How often do you backup your files?
 

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Testing Configuration and Setup

Hardware and Software Setup

The list of hardware and software is shown in the following table.

Hardware

Software

 

Backup Server
(Backup destination)

- Intel Xeon 2.8GHz
CPU
- 2GB ram

- RedHat Enterprise
Linux AS4
- Storage Vault Offsite Backup
Server v.5.0.1.4

Client Workstation
(Backup source)

- Intel Pentium Dual-
Core CPU 3.2 GHz
- 2GB ram

- Intel Pentium Dual-
Core CPU 3.2 GHz
- 2GB ram
 

Test Scenarios

Overview

In the test, there are 4 file backup sets, each contains files of different numbers and sizes as described in the following table.

File Backup
Set

Average
file size

Total
number of
files

Number of
folders

Total Size
(GB)

Compressed
Size (GB)

Small-files

2Kb

1903685

1007

2.45

1.96

Medium-files

200Kb

10000

1010

2.38

1.90

Large-files

20Mb

100

10

2.44

1.95

Huge-files

200Mb

10

1

2.44

1.95

 

Test Cases

All 4 backup sets are with the following settings:

a Transfer block size is 128 Kb

b "In-File Delta" opyion is turned off

c Encryption is enabled (AES - CBC mode)

 

We have tested with different network bandwidths (uplink) for each of the backup set. The network constraint was achieved by limiting the bandwidth of the particular backup account with the following assumptions:

1. ADSL and SDSL have a down/up bandwidth
    up to 1.5Mbps/640Kbps and 2Mbps/2Mbps respectively.
    From trace route, they have gone through 12 routers/networks
    before reaching the Backup Server.

2. T1 has a bandwidth up to 1.544Mbps.

3. LAN has a bandwidth up to 100Mbps.

4. The average compression ratio of the files is only 80%.

 

Results

Upload Time

The time required for the backup operations with different network bandwidth are summarized below:

 

Test Case

Network Banwidth

(down/up)

Actual/Compressed

Size(GB)

Time taken

(HH:MM:SS)

Transfer rate

(MB/min)

 

Small-flles

(2 kb)

 

ADSL (1.5 Mbps/640Kbps)

2.45 / 1.96

15:12:17

2.2

SDSL (2 Mbps/2 Mbps)

2.45 / 1.96

05:22:41

6.22

T1

2.45/1.96

05:22:09

6.23

LAN

2.45 / 1.96

05:21:38

6.24

 

 

Medium-files

(200 kb)

 

ADSL (1.5 Mbps/640Kbps)

2.38 / 1.90

13:04:31

2.48

SDSL( 2Mbps/2Mbps)

2.38 / 1.90

04:23:38

7.83

T1

2.38 / 1.90

03:10:22

10.22

LAN

2.38 / 1.90

00:49:37

39.21

 

 

Large-files

(20Mb)

 

ADSL (1.5Mbps/640Kbps)

2.44 / 1.95

13:12:23

2.52

SDSL (2Mbps/2Mbps)

2.44 / 1.95

04:29:07

7.42

T1

2.44 / 1.95

03:05:14

10.78

LAN

1.44 / 1.95

00:31:24

63.6
 

 

Huge-files

(200Mb)

 

ADSL (1.5Mbps/640Kbps)

2.44 / 1.95

13:38:22

2.44

SDSL (2Mbps/2Mbps)

2.44 / 1.95

04:25:11

7.53

T1

2.44 / 1.95

03:12:11

10.39

LAN

2.44 / 1.95

00:59:57

33.31

 

Observations

For a backup set with a large number of small files, there is not much improvement in the backup speed even though the bandwidth has been increased. The bottleneck is thus on client workstation where the files are being processed and encrypted.

 

For a backup set with an average number of medium-sized files, increasing the uplink bandwidth does improve the backup speed by a significant amount. This reflects that, with lesser number of files, the bottleneck is switched to the network instead. In other words, the larger the number of files, the more processing is required on the SBA machine.

 

And for a backup set with smaller number of large files, similar patterns are observed. Namely, the backup speed is significantly improved when the uplink bandwidth is increased.

 

Conclusion

The time required for a backup (or backup speed) depends very much on the backup set’s constitution. Other than uploading a large number of files (over 2 million files) in a single backup, network latency is the major constraint on the backup speed.

 

In general, for a large number of small files (e.g. File system backup), the uplink bandwidth is relatively less important as the stress would be on the CPU of the source machine. In this case, a more powerful SBA machine could improve the backup speed. On the other hand, with smaller number of big files (e.g. MS Exchange, MS SQL backups), the available uplink bandwidth would have bigger impact on the overall backup speed.

 

At the planning stage, system administrators should choose the most cost-effective bandwidth in their situations. Following are some of the factors that they might need to consider:

 

a Type of backups

b Anticipated data volume

c Backup frequency

d Performance criteria

e Budget constraints

f  Trade off between performance and costs

g Expected growth in data volume

 

 

 
 
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Compatible With

windows

Windows
•95 •98 •ME •NT
•2000 •XP •VISTA •7

Windows SERVER
•2000 
•2003 •2003R2
•2008 •2008R2
mac Mac OS X
v10.x
linux Linux
Kernel 2.2 or above (e.g. Redhat 6.0 or above)
Sun_solaris Sun Solaris
2.5 or above
Novell_NetWare Novell NetWare
5.1 or above

javalogo

 Java

Compatible With

exchange

logo_sql_server

oracle

lotus

mysql

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