一直在找一顆輕薄短小、大容量的行動硬碟, 本想入手Seagate Backup Plus V2 Slim 2TB,
前不久看到這顆Seagate Backup Plus Ultra Slim 2TB ,價錢跟V2一樣, 3K以內可以接受,
就直接下訂了.
開箱:簡單的吊卡包裝
本體及說明書
與Fujitsu 500G(左)外觀比較, 9.6mm的厚度硬是小了一號
與SP 1T(左)對比,可以明顯看出厚度差異;USB3.0接口置中,上蓋右邊條狀是類似呼吸燈的讀寫指示燈
背部塑膠底殼,logo條紋造形很有特色,防滑防刮
採用ST2000LM007 5400rpm
讀寫效能比我預期中要好, 實際存取檔案時有令人驚艷的速度表現(與我手邊現有1T 2.5"比對)
我最重視的攜帶重量120.5克, 對比其他行動碟差了30克左右,放在口袋的差別很有感
以上簡單分享~
SMR~不適合系統用,隨機寫入很慢,冷儲存,大陸製
So this model now is based on ST2000LM007-1R8174 SATA harddrive, which is 7mm thick and uses SMR recording technology.
(before Summer 2016 they had used to put ST2000LM003 drives inside this model of the external drive, which were 9 mm thick and used PMR recording).
It is usable as a bulk cold storage archival drive, provided small random writes are minimised.
In order to get a satisfactory performance on a windows PC, do the following:
1. After connecting it to the PC, On windows, Right click on computer -> manage -> device manager -> disks -> Seagate Expansion -> Policies tab -> set to better performance, + enable write caching & disable buffer flushing. (Also it is applicable to some USB flash/SSD disks).
2. After receiving the new disk, before filling with data, quick format this drive with 64KB clusters (NTFS filesystem), For linux user, do not use ext3/4! (unless using packed metadata option, google: SMR drives in linux), this is Drive Managed SMR, so could become very slow on writes (if used with stock ext3 FS) and does not like distributed FS metadata. For mac - it should be OK with HFS, provided 64KB blocksize is used.
3. Enable turbo USB (unless you are on win10 or have UASP usb3.0 controller) - set minimum USB BOTP transfer size to 1MB-2MB. Helps for usb2.0 speeds too :-)
4. When filling the drive with data, expect the writing speed to average at ~30MB/s after first 20GB, and do not be worried about clicks, since it has ~20GB of PMR cache, and once that is full or drive is idle, it has to move that data onto SMR region.
5. Once done with data copy, leave the drive on while it makes clicking sounds (so it can move all the data from PMR region to SMR section). Once the clicks had stopped, you can unmount and then safelly remove it. Unlike the previous PMR version, it does not spin down when idle for long time, so it is better not to leave it on constantly.
If this advice is followed, it would be fast for the first 20GB, next time it is used.
6. Do not use it for any dynamic database application or raid0, raid5 or raid6! (it can be sort of ok for soft RAID1, linear or JBOD backup archive)! Also make sure no swap file resides on it!
Also do not use it as working drive for P2P downloads, since it is not really designed for random writes. But it is ok with large random reads, so ok to be used as a storage for completed downloads (enable completeion move).
hwang0934 wrote:
我是樓主,請問你怎...(恕刪)
英文敘述您看了嗎?
因為看到特價很便宜,居然沒人搶,就覺得粉奇怪
當外接硬碟還可啦,當系統碟效能就慘了..
大量搬移完整檔案,會比一般快,但隨機就很慢了(英文都有寫阿)
去GOOGLE一下
另外我有20顆以上外接硬碟,我個人對外接硬碟不會期待效能,只要穩定就好~多少顆不重要,只是討論而已,讓大家知道現在技術
如同SSD:SLD,MLD,TLD 討論而已
轉述PCDVD:作者sanpig101
[東芝Toshiba]
目前持續深化使用PMR垂直寫入磁記錄技術, 不考慮不成熟有問題的技術才是對消費者負責任的態度
1.3.5吋部分...最新的...出到6TB, 單碟最大1.2TB
2.2.5吋部分...最新的...出到2TB, 未來將使用PMR技術出3TB
東芝表示不會跟進SMR疊瓦式寫入磁記錄, 這會對使用者造成非常大的麻煩...
PMR技術是目前技術最為成熟的技術....
[希捷Seagate]
全面進入SMR疊瓦式寫入磁記錄技術, 未來以歸檔硬碟(冷儲存硬碟)取代桌面硬碟與NAS硬碟....
1.3.5吋部分...已確認5TB以上容量全面採用
2.2.5吋部分...未來超出2TB以上容量將全面採用(例如3TB)
SMR技術以重疊磁軌來提升磁密度, 其方式類似磁帶或空白光碟, 一次性使用不會有太大問題。但問題最大的是超出一次以上的隨機寫入, 這會造成大量磁軌須重新寫入, 這就像是SSD中的SandForce系列晶片使用的壓縮特性雷同, 會造成大量的效能損失。例如目前香港討論區中, 希捷AS系列5~8TB的問題與BUG可見一斑, 寫入速度會越來越慢, 還會慢到低於每秒10MB以下, 此外因重覆寫入重疊磁軌造成了大量壞軌與資料遺失等問題。(這也是為什麼東芝Toshiba放棄此一技術, 還是採用最成熟最沒問題的PMR技術)
另外....此一技術完全不適合使用在會有大量亂數寫入的P2P上面, 這樣硬碟速度會極慢, 資料也將會大量遺失與大量壞軌.......
[HGST]
目前逐漸導入氦氣與SMR技術
1.3.5吋部分...已確認5~8TB採用氦氣+PMR, 而10TB以上採用氦氣+SMR
2.2.5吋部分...未來超出2TB以上容量將全面採用(例如3TB)
[WD]
未來將導入SMR技術
1.3.5吋部分...已確認新推出的5~6TB都還是PMR技術, 10TB以上使用SMR技術...
2.2.5吋部分...目前還是PMR技術
總結
1.如果要用P2P的話, 請跳過SMR技術的硬碟.....選擇PMR技術硬碟比較安全....
2.如果只是要備份, 備份後就不再使用, 那選擇SMR技術硬碟比較能省錢....
3.SMR技術在多次亂數寫入會類似SSD的髒碟降速的問題, 目前仍是無解....
4.SMR技術重覆寫入同一軌段資料, 會使磁盤壽命大幅減損, 也會產生大量壞軌, 目前仍無解法....
各位站友可能要視需求去購買硬碟, 這也是為什麼希捷會稱之"歸檔硬碟"了....
cq5388 wrote:
想請問:可以告知這...(恕刪)
These drives provide the following key features:
• 1000 Gs non-operating shock and 400 Gs of operating shock.
• 128MB buffer.
• 5400-RPM spindle speed.
• Full-track multiple-sector transfer capability without local processor intervention.
• High instantaneous (burst) data-transfer rates (up to 6Gb/s).
• Native Command Queuing (NCQ) with command ordering.
• Perpendicular recording technology.
• Quiet operation. Fluid Dynamic Bearing (FDB) motor.
• SeaToolsTM diagnostic software performs a drive self-test that eliminates unnecessary drive returns.
• State-of-the-art cache and on-the-fly error-correction algorithms.
• Support for Read Multiple and Write Multiple commands.
• Support for S.M.A.R.T. drive monitoring and reporting.
• Worldwide Name (WWN) capability uniquely identifies the drive.
官方PDF的資料
因該是PMR
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