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42039
December 1st, 2015 09:00
SC4020 Build Single Tier
Does anyone have any opinion on building out SC4020 with Single Tier 3.8TB Mainstream Read-Intensive drives (TLC) - 40TB usable.
DPACK Info:
7000 IOPS at peak, 2500 IOPS at 95%
60% / 40% - Read / Write
28 TB Data storage in use.
2.5 TB Average Daily Writes
400 MB / s Peak Network Throughput
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cpetry
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December 2nd, 2015 20:00
TLC is rated for 1,000 to 5,000 erase/write cycles per cell. I don't think I would implement a system with just TLC if you have 40% write. 2.5TB of daily writes is a lot for TLC in my opinion. We write 500-1000GB per day and Dell is already pressuring us to upgrade our tier 1 (SLC).
I have one six pack of SLC to absorb the random writes. Then data progression kicks off and pushes everything down into tier 2 (MLC).
If you can get an SC4020 with SCOS 6.7.3 installed you can enable compression on the second tier. If you need the space... I"m unsure about the performance impact. I'm actually researching this right now.
BTW - SLC is rated for 100,000 erase/write cycles per cell.
Update:
SC4020 build:
Tier 1: 6 x 800 GB SLC (4 TB)
Tier 2: 6 x 3.84 TB TLC (19.2 TB)
Total usable: 23.2 TB before RAID overhead (single redundancy will have about 11% overhead)
You have 28 TB of data. Compression on DCOS 6.7.3 will compress both frozen accessible and frozen inaccessible data.
From what I've read this will yield an average reduction of around 35%. There are articles online stating some corporations are seeing higher compression savings. It would also depend greatly on what kind of data you have. Audio/video files don't compress well.
That should put your data footprint around 18 TB.
You can always budget for another 6 pack of TLC next year and disable compression later if you think it's hurting performance.