TY - GEN
T1 - CachedGC
T2 - 26th IEEE International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2018
AU - Shahidi, Narges
AU - Kandemir, Mahmut T.
N1 - Funding Information:
This work is supported in part by NSF grants 1526750, 1763681, 1439057, 1439021, 1629129, 1409095, 1626251, 1629915, and a grant from Intel.
Publisher Copyright:
© 2018 IEEE.
PY - 2018/11/7
Y1 - 2018/11/7
N2 - Solid State Drives (SSDs) have many attractive features, and they are well-positioned to replace traditional HDDs in cloud and enterprise storages. However, some specific features they have such as erase-before-write and limited erase count make this transition more challenging. To tackle the issues brought by these features, Flash Translation Layer (FTL) leverages functionalities such as Garbage Collection (GC) to provide free space by erasing the blocks and cleaning the stale data. This process occupies SSD resources and causes extra waiting time for normal IO requests, and ultimately increases response time. Cloud workloads include many applications with small random write access patterns which cause frequent GC invocations. Flash occupation at the time of GC causes inconsistent performance and increases tail latency which may in turn violate SLA in these applications. In this paper, we modify the conventional GC process and propose a Cache-Assisted Garbage Collection (CachedGC). CachedGC postpones writing back valid pages during the GC, erases the block at the first possible time, and hence resumes normal SSD operations sooner. CachedGC reduces request response time and tail latency by reducing the effective latency of GC. Our experimental results using a variety of workloads show that CachedGC reduces read tail latency by 19% and improves write IOPS by as much as 27%.
AB - Solid State Drives (SSDs) have many attractive features, and they are well-positioned to replace traditional HDDs in cloud and enterprise storages. However, some specific features they have such as erase-before-write and limited erase count make this transition more challenging. To tackle the issues brought by these features, Flash Translation Layer (FTL) leverages functionalities such as Garbage Collection (GC) to provide free space by erasing the blocks and cleaning the stale data. This process occupies SSD resources and causes extra waiting time for normal IO requests, and ultimately increases response time. Cloud workloads include many applications with small random write access patterns which cause frequent GC invocations. Flash occupation at the time of GC causes inconsistent performance and increases tail latency which may in turn violate SLA in these applications. In this paper, we modify the conventional GC process and propose a Cache-Assisted Garbage Collection (CachedGC). CachedGC postpones writing back valid pages during the GC, erases the block at the first possible time, and hence resumes normal SSD operations sooner. CachedGC reduces request response time and tail latency by reducing the effective latency of GC. Our experimental results using a variety of workloads show that CachedGC reduces read tail latency by 19% and improves write IOPS by as much as 27%.
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U2 - 10.1109/MASCOTS.2018.00015
DO - 10.1109/MASCOTS.2018.00015
M3 - Conference contribution
AN - SCOPUS:85058312280
T3 - Proceedings - 26th IEEE International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2018
SP - 79
EP - 86
BT - Proceedings - 26th IEEE International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2018
PB - Institute of Electrical and Electronics Engineers Inc.
Y2 - 25 September 2018 through 28 September 2018
ER -