随着越来越多企业开始关注云计算，云应用也逐渐普及开来，例如利用云进行杀毒，查杀木马，同步以及备份等。相比于杀毒软件，目前对于普通用户来说，利用云来同步及备份更为成熟且实用。最近几年很多企业提供了云备份功能，其中有收费的也有面向一般用户的免费服务。以下就对目前流行的几款免费云同步与备份软件进行比较。

云应用	Dropbox 推荐链接	IDrive	onedrive.live.com	Mozy	SpiderOak	SugarSync 推荐链接(not free)	Syncplicity (not free)	ZumoDrive (已停止服务）
平台	Mac Windows Linux	Mac Windows	Mac Windows	Mac Windows	Mac Windows Linux	Mac Windows	Mac Windows	Mac Windows
移动平台	支持	支持	支持	不支持	不支持	支持	支持	支持
Web 访问	支持	支持	支持	有限支持	支持	支持	支持	支持
空间大小	2G	5G	5G	2G	2G	5G	2G	2G
推荐奖励	250M/人 最多8G	发送推荐 最多10G	无	256M/人 最多3G	无	250M/人（推广期：500M/人）	1G/人 最多3G	无
最大容量	10G+（其他奖励活动有额外奖励）	12G	5G	5G	2G	10G（推广期：无限制）	6G	2G
设备限制	无限制	限制	无限制	2台	无限制	2台	2台	无限制
同步	支持	单机同步	支持	不支持	支持	支持	支持	支持
备份	不支持	增量	不支持	增量	增量	增量	增量	支持
带宽控制	自定义	自定义	无限制	自定义	自定义	强制限速	自定义	无限制
传输加密	SSL	128-bit SSL	SSL	128-bit SSL	SSL	SSL	128-bit SSL	SSL
存储加密	AES-256	AES-256	RSA+AES-128	448-bit Blowfish / AES-256	2048 byte RSA / AES-256	AES-128	AES-256	AES
文件限制	无限制	无限制	无限制	无限制	无限制	无限制	无限制	无限制
版本控制	30天	30个版本	不支持	30天	所有	3个版本	所有	所有
分享	支持	不支持	支持	不支持	支持	支持	支持	支持
外链	支持	不支持	不支持	不支持	不支持	支持	不支持	不支持
进程	1个	4个	2个	2个	2个	1个	1个	1个
备注	iPhone客户端目前还在开发阶段。客户端上传无限制，Web上传最大350M。基于Amazon S3。 【2009-09-30 更新：Dropbox 推出 iPhone 版客户端】 【2010-12-29 更新：由于众所周知的问题，国内无法正常访问。】	Mac与Windows不能使用同一账户，因为Idrive不支持同一账户的多台机器的备份，但可以将已有备份恢复到任意机器上。 【2010-12-19 更新：iDrive 现在有两种版本，一种是同步，一种是备份。】	Mac版处于封闭测试阶段。 【2010-12-19 更新：已并入 Live Skydrive 中。】	登录后申请恢复，通过收电子邮件来获得下载地址，且有效期为7天，只能使用一次，再次使用需要重新申请。	未来开源或支持OLPC。	免费账户有上传速度限制。 【2009-10-09 更新：SugarSync 支持完全外链，其他用户无需注册或打开下载页面即可直接下载文件】 【2010-04-03更新：官方已经提供简体中文网站】	Mac版只支持Intel CPU的机器，暂未有支持PowerPC的计划。另由于，Mac版设计问题，已经停止提供且原有的客户端已无法访问，新版本会在明年发布。 【2010-04-03 更新：可以与 Google Docs 进行连接并同步】 【2010-04-28 更新：Mac 版开始测试】	文件存储在Amazon S3云服务器上，通过磁盘映射在本地进行操作。基于Amazon S3。

目前软言软语使用的是 Dropbox + Live Mesh 的组合 Dropbox，为的是稳定性和速度。当然 Live Mesh 目前还处于测试版，会有不少问题，但鉴于微软的实力，其稳定性应该毋庸置疑。 而 Dropbox 基于 Amazon S3的存储服务，稳定性也是不错的，又支持外链和版本控制，在我这里速度也很快，占用资源也不多。对于其他几款软件，因人和目的的不同，选择自然也不同。iDrive 和 Mozy 致力于完全的备份，所以不适合想要同步功能的人，iDrive 的资源占用也令人咋舌，相比而言 Mozy 稍好，但其日志文件增长十分迅速，即使把服务关了也还在记录，如果你发现硬盘空间少了，不妨查看一下 X:\Program Files\MozyHome\Data\filter_raw.log 的文件大小（X为安装盘）。目前，iDrive 是这里面免费空间容量最大的，而且获得奖励空间也相对容易，只要发送邀请即可，不需要被邀请人进行注册，不同于其他几款软件。Syncplicity 个人认为还是值得关注的，同步和备份做的都不错，但似乎在 Mac 客户端开发上出现了一些问题。而 ZumoDrive 严格意义上来说，只能算是网盘了，所有要备份的文件需要拖拽到其映射的磁盘中。值得一提的是，ZumoDrive 也是基于 Amazon S3 的服务。
【2010-12-19 更新】由于众所周知的原因，Dropbox 已经有很长时间不能在国内正常访问了，后来当 Dropbox 在国内无法访问以后，似乎使用条款有所修改，取消了这一限制，但愿以后不会再改回去。
【2012-11-08 更新】freewaregenius 上的一篇对大部分云存储服务的比较文章，《A comparison of FREE Cloud Storage Services》。
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A comparison of FREE Cloud Storage Services

 Now that the biggest tech companies in the world are taking aim at Dropbox (with Microsoft, Apple, and Amazon all offering their own cloud storage services), we thought we would compare the FREE cloud storage plans that are out there, in terms of how much free storage space they offer, how easy it is to get it raised, and how much you could get in total.

We also compare other pertinent factors that could help you decide which one is best for you.
We tried to list all the “good” cloud storage services; however, there were criteria for inclusion on our list, as well as criteria for exclusion (see below for more info on both).
Our list eventually encompassed the following: , Dropbox, Skydrive, Amazon Cloud Drive, Google Drive , Sugarsync, Glide , CX (Cloud Experience), Memopal, Safecopy, Mimedia, Teamdrive, HiDrive, Comodo Cloud Storage, Spideroak, MegaCloud, Wuala, and Synplicity.
Note: this is a snapshot of the way things were as of our last update: May 1st, 2012. Things could have changed since. If you find an inaccuracy, please let us know in the comments or via email.

How much free storage do I need?

Although the answer to this question is up to you, this issue was explored in a previous post entitled “How much free cloud storage space do you really need?”, which posited that 7 gigs may be the magic number.

Inclusion criteria: what the services have to offer to be on the list

• A free plan: obviously
• Desktop folder sync: a desktop client that syncs a local folder or folders with the cloud.  Services that offer this only with a paid plan were excluded. This is also why most ‘file locker’ type services were excluded.

The Comparison

• Sorting order: the services on the list below are sorted in descending order according to the amount of maximum free storage attainable for each.
• Recommendations: if you want to know which services we like here at Freewaregenius, go to the ‘recommendations’ section below.
• Links: go down to the links section for sign-up links. In most cases you will get the initial extra referral bonus.

[1] This will also depend on your browser or OS file size limits
[2] We couldn’t find documentation for this, but found it in practice
[3] Safecopy seems to be a mere rebranded copy of Memopal, with a few minor differences between the two,
[4] Legacy accounts have 25 gigs free, and if you have a Hotmail or MSN account you may be able to get 25 gigs as well (see the recommendations section below)
[5] It may be possible to get more if you’re buying music off of Amazon (see here)
[6] Not 100% sure about this.

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Links (intended in many – but not all – cases to start you off with a bonus)

Idrive	HiDrive
Sugarsync	Comodo Cloud Storage
Glide	Spideroak
Dropbox	MegaCloud
CX (Cloud Experience)	Wuala
Memopal	Skydrive
Safecopy	Amazon Cloud Drive. Desktop client here.
Mimedia	Google Drive
Teamdrive	Synplicity

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Exclusion criteria: why some services are excluded from the list

• No desktop client in the free version: Box.net, sadly, and Adrive are guilty of this.
• Maximum attainable free storage @ 2 gigs or less: if you can only get 2 gigs free maximum storage no matter what, we excluded the service. Mozy is an example.
• Mac only, or requires ownership of an Apple device: Apple’siCloud, and Dolly Drive were excluded on this basis.
• Free versions have bandwidth or speed restrictions: with so many options available, we decided to toss out the following services that restrict daily or monthly bandwidth in the FREE version, or restrict upload speed: YouSendIt (1GB/month restriction), OpenDrive (1GB/Day, 200KB max upload speed), FilesyncAnywhere (25MB per file, max 25 files per day) , and Asus WebStorage (500MB per day).
• Defunct services or ones that are being phased out: ZumoDrive and Windows Live Mesh fall into this category.
• Unclear or misleading offering: ZenOK was tossed out because it doesn’t know what it is and what it wants to offer.
• No free plan available: many services were overlooked on this basis.

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Our recommendations:

We like SkyDrive, Dropbox, iDrive, and Google Drive. But we also like many of the others.

• We like Skydrive because you can get it installed on multiple computers at once (on a single account), and you can likely still get the 25 gigs if you have a Hotmail or MSN login, see this link and this LifeHacker article.
• We like Dropoxbecause it is widespread, such that you will NOT need to ask your friends and collaborators to sign up for something entirely new, since they will likely already have a Dropbox account. It is also being widely used by developers who are creating cloud-related apps. The current maximum free offering (16 gigs) from Dropbox will is on the higher end of the table, and is probably sufficient for most people’s needs.
• We like iDrivebecause you can get up to 50 gigs of free space, at 1 gig increments per friend.
• We like Google Drive because we use Gmail and many other Google services.

But we are working on another post that compares these services more thoroughly, including their unique strengths and weaknesses, beyond how much free space they offer. We would like your input.

from http://www.freewaregenius.com/a-comparison-of-free-cloud-storage-services/
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Get cloud access to anything on your PC, with TackaCloud’s ‘Personal Cloud’

 Although Dropbox and other cloud services have gotten us used to accessing our files anywhere from the cloud, somehow there is always that important file (or files) that you need that are not in your cloud-shared folder. Moreover, you likely do not sync many large files (suchas media files) to Dropbox in order not to exceed your file storage limits, and therefore do not have remote access to them on demand.StoAmigo’s TackaCloud (for Windows, Mac) might be a way to remedy these issues by providing you with your own “Personal Cloud”, enabling you to selectively access an entire shared drive or folder on your PC without any size limitations, and uploading it only on demand. The only limitation: that your computer at home be switched on and online to upload or download from.

The other usage of course is to sending large files. Instead of using send-large-file services like WeTransfer or Jumpshare, you can simply share it from the TackaCloud’s web app. What’s really nice is that you can share folders and not just files, and changes in the content of a shared folder will be reflected/updated every time your collaborators access your link that you emailed them, and the person you share with does not have to have a StoAmigo/TackaCloud account. The drawback again (unlike send large file services) is that your computer has to be online or your collaborator will end up with an error message. The upside of this, of course, is simply added security: yes you have to be online but at least copies of your data are not residing on a server somewhere. Alternately if you don’t want this limitation you can simply move your files to the 5 GIGs of traditional free cloud storage also provided by StoAmigo/TackaCloud, and which is accessible via the same interface.

 

Please note that I use the terms TackaCloud and TackApp interchangeably in this post. They are the same thing. Also to clear things up a little bit: TackaCloud is a service provided by StoAmigo, a Dropbox-like cloud service that provides 5 gigs of free online storage. Installed on your PC or Mac (or Android/iOS), TackaCloud lets you access both your StoAmigo online storage as well as your folders shared via TackaCloud on your PC (again, if that PC happens to be online). It also enables you to move files easily from one to the other via drag and drop.
Below: list of PROs and CONs related to the TackApp service, and a comparison with BiTorrent Sync, which provides the same functionality, in the verdict section.
PROS:

1. A really great way to have  access to anything on your PC, not just files saved in pre-determined folders. Of course this is provided that that PC, wherever it physically resides, is turned ON and is online. (Alternately, just call and tell someone at home to turn the computer on ).
2. Send large files easily and more securely, given that remote copies of your files do not exists out in cyberspace.
3. Your files are only uploaded when you request them, and your internet connection (and bandwidth) will not be constantly clogged (and used up) when new files are added or removed, during the course of working normally on your PC.
4. Right click to share folders: actually this is a promised feature not available in the version I looked at, but promised by the developers.
5. Also Promised:

CONS:

1. General Slowness: navigating and accessing my stuff was slow and plodding. This was true in general but seemed more so on Android than the web app. I’m hoping that this will be tweaked by it’s eventual release.
2. Confusing user experience with the Android app: I know the mobile apps are still in development, but seriously this might be a deal breaker.  For example In the Android app, it doesn’t seem possible to select multiple files/folders simultaneously to download on the device, forcing the user to download serially. A small tweak would make the app a lot more useable.
3. I’m not really comfortable with sharing an entire drive, for security and privacy reasons, even with the promise that nothing is uploaded to a remote server. Much better to be able to specify many individual folders to share (which is promised).
4. No cloud backup: because your files are not actually uploaded, TackApp is unlike normal cloud services in that it cannot be relied on as cloud backup service. This is not really a ‘con’ since the app never pretends to provide this, but I suppose it is an argument for using traditional cloud services in lieu of this sort of ‘person cloud’.
5. The desktop app needs finessing: for example minimizing to tray, the option to start on boot, to store the password, to share more than one drive as mentioned (or folders on more than one drive), and of course the promised feature to be able to right click to share a folder.

The Verdict:
This is a great app to have if you want to remote access to all your files on the go. I may be disinclined to leave it running at all times (or to leave my PC on at all times), but I know that if I do I can always ask my wife or children to turn on both the PC and TackApp if I need to. It’s also a great way to share large files with people without uploading them to an external server.
Of course, I could not end a writeup of TackApp without comparing it to BitTorrent Sync, another app which does the same thing. Sync seems to perform better right now, in terms of speed of accessing and downloading files. This is perhaps because Sync handles a set of individual folders on demand rather than an entire drive, and perhaps because it uses the tried, tested (and optimized?) torrent network to do what it does. However, the free version of Sync limits the number of folders you can share, and doesn’t provide the 5 free gigs of cloud storage which TackApp does.
TackApp is still in beta, though, and the three items on my wish list for it are: (1) faster handling of files and better responsive; (2) a better mobile app experience, and (3)  I would very much love to be able to share files on my device back to my PC from the same platform.
One thing is certain: I will be watching the development of this software with a lot of interest.
Visit the TackApp site for more info. Download links here (Windows, Mac).

from  http://www.freewaregenius.com/get-cloud-access-to-anything-on-your-pc-with-tackaclouds-personal-cloud/