In this tutorial, I will show you How To Install Django In Mac. Django is available open-source under the BSD license. We recommend using the latest version of Python 3. If you plan to use Django’s database API functionality, you’ll need to. The corporate edition (CMR) is designed with HIPAA rules and designed for the medical professional. Downloads: 0 This Week Last Update: 2013-03-26 See Project With one platform, you can get more work done — from anywhere, on any device. SMR has worse sustained write performance than CMR, which can cause severe issues during resilver or other write-intensive operations, up to and including failure of that resilver. It is often desirable to choose a CMR drive instead. This thread attempts to pull together known SMR drives, and the sources for that information.
Hard drives that write data in overlapping, 'shingled' tracks, have greater areal density than ones that do not. For cost and capacity reasons, manufacturers are increasingly moving to SMR, Shingled Magnetic Recording. SMR is a form of PMR (Perpendicular Magnetic Recording). The tracks are perpendicular, they are also shingled - layered - on top of each other. This table will use CMR (Conventional Magnetic Recording) to mean 'PMR without the use of shingling'.SMR allows vendors to offer higher capacity without the need to fundamentally change the underlying recording technology.
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SMR is well suited for high-capacity, low-cost use where writes are few and reads are many.
SMR has worse sustained write performance than CMR, which can cause severe issues during resilver or other write-intensive operations, up to and including failure of that resilver. It is often desirable to choose a CMR drive instead. This thread attempts to pull together known SMR drives, and the sources for that information.
There are three types of SMR:
- Drive Managed, DM-SMR, which is opaque to the OS. This means ZFS cannot 'target' writes, and is the worst type for ZFS use. As a rule of thumb, avoid DM-SMR drives, unless you have a specific use case where the increased resilver time (a week or longer) is acceptable, and you know the drive will function for ZFS during resilver. See (h)
- Host Aware, HA-SMR, which is designed to give ZFS insight into the SMR process. Note that ZFS code to use HA-SMR does not appear to exist. Without that code, a HA-SMR drive behaves like a DM-SMR drive where ZFS is concerned.
- Host Managed, HM-SMR, which is not backwards compatible and requires ZFS to manage the SMR process.
I am assuming ZFS does not currently handle HA-ZFS or HM-ZFS drives, as this would require Block Pointer Rewrite. See page 24 of (d) as well as (i) and (j).
List of SMR drives known to the community:
| Manufacturer - Width | Model No | Model Name | Type | Notes |
| WD - 3.5' | WD20EFAX | 2TB WD Red | DM-SMR | (1) and (4), EFRX is CMR |
| WD - 3.5' | WD30EFAX | 3TB WD Red | DM-SMR | (4), EFRX is CMR |
| WD - 3.5' | WD40EFAX | 4TB WD Red | DM-SMR | (1) and (4), EFRX is CMR |
| WD - 3.5' | WD60EFAX | 6TB WD Red | DM-SMR | (1) and (4), EFRX is CMR |
| WD - 3.5' | WD20EZAZ | 2TB Blue | DM-SMR | (4), EZRZ is CMR |
| WD - 3.5' | WD30EZAZ | 3TB Blue | DM-SMR | ?, EZRZ is CMR |
| WD - 3.5' | WD40EZAZ | 4TB Blue | DM-SMR | ?, EZRZ is CMR |
| WD - 3.5' | WD60EZAZ | 6TB Blue | DM-SMR | (4), EZRZ is CMR |
| WD - 3.5' | Various | All 2-6TB external drives - Elements, My Book, Easystore, etc. Precise models vary and are not guaranteed; assume SMR in capacities below 8TB. | DM-SMR | (12), (14) |
| Seagate - 3.5' | ST2000DM005 | 2TB Barracuda | DM-SMR | (8) |
| Seagate - 3.5' | ST2000DM008 | 2TB Barracuda | DM-SMR | (2) |
| Seagate - 3.5' | ST3000DM007 | 3TB Barracuda | DM-SMR | (8) |
| Seagate - 3.5' | ST4000DM004 | 4TB Barracuda | DM-SMR | (2) |
| Seagate - 3.5' | ST5000DM003 | 5TB Barracuda | DM-SMR | (8) |
| Seagate - 3.5' | ST6000DM003 | 6TB Barracuda | DM-SMR | (8) |
| Seagate - 3.5' | ST8000DM004 | 8TB Barracuda | DM-SMR | (2) |
| Seagate - 3.5' | ST5000DM000 | 5TB Desktop | DM-SMR | (2) |
| Seagate - 3.5' | ST5000AS0011 | 5TB Archive | DM-SMR | (3) |
| Seagate - 3.5' | ST6000AS0002 | 6TB Archive v2 | DM-SMR | (3) |
| Seagate - 3.5' | ST8000AS0002 | 8TB Archive v2 | HA-SMR | (3) and (10) |
| Seagate - 3.5' | ST8000AS0003 | 8TB Exos (Archive v3) | DM-SMR | (2) |
| Seagate - 3.5' | ST1000VX008 | 1TB Skyhawk Lite | DM-SMR | (8) |
| Seagate - 3.5' | ST2000VX007 | 2TB Skyhawk Lite | DM-SMR | (8) |
| Toshiba - 3.5' | HDWD240UZSVA | 4TB P300 Desktop | DM-SMR | (11) |
| Toshiba - 3.5' | HDWD260UZSVA | 6TB P300 Desktop | DM-SMR | (11) |
| Toshiba - 3.5' | DT02ABA400 | 4TB DT02(-V) | DM-SMR | (11) |
| Toshiba - 3.5' | DT02ABA600 | 6TB DT02(-V) | DM-SMR | (11) |
| HGST - 3.5' | DC HC600 Series | 14TB, 15TB and 20TB Ultrastar | HM-SMR | (9) |
| --- | --- | --- | --- | |
| Toshiba - 2.5' | HDWL110 | 1TB L200 Slim | DM-SMR | (11) |
| Toshiba - 2.5' | HDWL120 | 2TB L200 | DM-SMR | (11), see also list at (18) |
| Toshiba - 2.5' | MQ04ABF100 | 1TB MQ04 | DM-SMR | (11) |
| Toshiba - 2.5' | MQ04ABD200 | 2TB MQ04 | DM-SMR | (11) |
| WD - 2.5' | WD9000LPZX | 900GB Blue | DM-SMR | (16) |
| WD - 2.5' | WD10SPZX | 1TB Blue | DM-SMR | (4), also as HGST Travelstar, see (20) |
| WD - 2.5' | WD10SPWX | 1TB Blue | DM-SMR | (16) |
| WD - 2.5' | WD10SPSX | 1TB Black | DM-SMR | (4) |
| WD - 2.5' | WD20SPZX | 2TB Blue | DM-SMR | (4) |
| WD - 2.5' | Various | Not For Resale | DM-SMR | List at (17) |
| Seagate - 2.5' | ST1000LM048 | 1TB Barracuda | DM-SMR | (7), see also list at (19) |
| Seagate - 2.5' | ST2000LM015 | 2TB Barracuda | DM-SMR | (7), see also list at (19) |
| Seagate - 2.5' | ST3000LM024 | 3TB Barracuda | DM-SMR | (7), see also list at (19) |
| Seagate - 2.5' | ST4000LM024 | 4TB Barracuda | DM-SMR | (7), see also list at (19) |
| Seagate - 2.5' | ST5000LM000 | 5TB Barracuda | DM-SMR | (7), see also list at (19) |
| Seagate - 2.5' | All current Barracuda, Firecuda, Skyhawk Lite/Mini models | DM-SMR | (8) |
More info on SMR:
(a) HA-SMR and HM-SMR in ZFS: 2014, Tim Feldman of Seagate, http://open-zfs.org/w/images/2/2a/Host-Aware_SMR-Tim_Feldman.pdf
(b) HA-SMR presentation, recording: 2014, Tim Feldman, https://www.youtube.com/watch?v=b1yqjV8qemU
(c) HA-SMR education: 2014, Mary Dunn and Tim Feldman of Seagate, https://www.snia.org/sites/default/...rial_Shingled_Magnetic_Recording-r7_Final.pdf
(d) ZFS on SMR: 2014, Robert Novak, https://storageconference.us/2014/Presentations/Novak.pdf
(e) HM-SMR paper: 2013, Albert Chen et al, WD: https://www.snia.org/sites/default/...Chen_JimMalina_Host_Managed_SMR_revision5.pdf
(f) DM-SMR and CMR zones, resilvering woes: https://blocksandfiles.com/2020/04/15/shingled-drives-have-non-shingled-zones-for-caching-writes/
(g) Code to make ext4 HA-SMR aware: 2015, Seagate, https://github.com/Seagate/SMR_FS-EXT4
(h) Performance and resilver results of using Seagata Archive v2 8TB on FreeNAS: https://www.ixsystems.com/community/threads/seagate-8tb-archive-drive-in-FreeNAS.27740/page-2
(i) The intricacies of BPR: 2013, Matt Ahrens, https://youtu.be/G2vIdPmsnTI?t=2675
(j) BPR is so complex no new features can be added afterwards: 2020, BSD Now podcast, from roughly 22:00, https://www.bsdnow.tv/340
(k) SMR presentation: 2015, Manfred Berger HGST, https://youtu.be/a2lnMxMUxyc
(l) OpenZFS Office Hour discussion on SMR: 2015, SMR, Resilvering, Possible Solutions at around 20, 31 and 46 mins respectively, https://youtu.be/mS4bfbEq46I?t=1220
(m) SAFS example file system for HA-SMR: 2015, Huewai R&D, https://www.snia.org/sites/default/...organ-An_SMR-Aware_Append_Only-FiveSystem.pdf
(n) HiSMRFs research file system for SMR: 2014, https://www.researchgate.net/public...rmance_file_system_for_shingled_storage_array
(o) Poster for Zone-based Storage Tiering for HA-SMA: 2017, University of Minnesota, https://sc17.supercomputing.org/SC17 Archive/tech_poster/poster_files/post204s2-file2.pdf
(p) Manylogs concept, platters would need SMR and CMR sides: 2016, IEEE, https://ieeexplore.ieee.org/document/7897075
(q) Toshiba presentation on SMR technology: 2015, https://www.toshiba.co.jp/tech/review/en/01_02/pdf/a08.pdf
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Sources for 'drive is SMR' assertions
(1) WD Red 2TB to 6TB are DM-SMR: https://blocksandfiles.com/2020/04/14/wd-red-nas-drives-shingled-magnetic-recording/
(2) Seagate drives that use DM-SMR: https://blocksandfiles.com/2020/04/15/seagate-2-4-and-8tb-barracuda-and-desktop-hdd-smr/(3) Seagate data sheet for DM-SMR Archive drives: https://www.seagate.com/www-content...dd/en-us/docs/archive-hdd-dS1834-3-1411us.pdf
(4) WD list of SMR drives: https://blog.westerndigital.com/wd-red-nas-drives/
(7) Anandtech lists Seagate 2.5' Barracuda as SMR: https://www.anandtech.com/show/1075...5-mobile-hard-drives-with-up-to-5-tb-capacity
(8) Seagate's list of SMR drives: https://www.seagate.com/internal-hard-drives/cmr-smr-list/
(9) HGST Host-Managed SMR DataCenter drives: https://www.westerndigital.com/products/data-center-drives/ultrastar-dc-hc600-series-hdd
(10) Seagate datasheet for 8TB Archive v2 showing HA-SMR: https://www.seagate.com/www-content...seagate-archive-hdd/en-us/docs/100795782a.pdf
(11) Toshiba's list of DM-SMR drives: https://toshiba.semicon-storage.com/ap-en/company/news/news-topics/2020/04/storage-20200428-1.html
(12) WD platter sizes: https://rml527.blogspot.com/2010/10/hdd-platter-database-western-digital-35_9883.html|
(13) WD data sheet for WD Red, note 256MB cache suggesting DM-SMR: https://documents.westerndigital.co...et-western-digital-wd-red-hdd-2879-800002.pdf
(14) WD platter sizes niche products: https://rml527.blogspot.com/2010/10/hdd-platter-database-western-digital-35.html
(15) Seagate platter sizes: https://rml527.blogspot.com/2010/10/hdd-platter-database-seagate-35.html
(16) WD platter sizes 2.5': https://rml527.blogspot.com/2010/10/hdd-platter-database-western-digital-25.html
(17) WD platter sizes 2.5 niche products: https://rml527.blogspot.com/2010/10/hdd-platter-database-western-digital-25_2393.html
(18) Toshiba platter sizes 2.5': https://rml527.blogspot.com/2010/09/hdd-platter-database-toshiba-25.html
(19) Seagate platter sizes 2.5': https://rml527.blogspot.com/2010/09/hdd-platter-database-seagate-25.html
(20) HGST platter sizes 2.5': https://rml527.blogspot.com/2010/09/hdd-platter-database-hitachi-25.html
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