Pilar González-Férez

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Current technology trends for efficient use of infrastructures dictate that storage converges with computation by placing storage devices, such as NVM-based cards and drives, in the servers themselves. With converged storage the role of the interconnect among servers becomes more important for achieving high I/O throughput. Given that Ethernet is emerging(More)
This paper presents the RAM enhanced disk cache project, REDCAP, a new cache of disk blocks which reduces the read I/O time by using a small portion of the main memory. The essential ideas behind REDCAP are to enlarge the built-in cache of the disk drive, imitate its behavior, and take advantage of its read-ahead mechanism by prefetching disk blocks. REDCAP(More)
Small I/O requests are important for a large number of modern workloads in the data center. Traditionally, storage systems have been able to achieve low I/O rates for small I/O operations because of hard disk drive (HDD) limitations that are capable of about 100-150 IOPS (I/O operations per second) per spindle. Therefore, the host CPU processing capacity(More)
Given current technology trends towards fast storage devices and the need for increasing data processing density, it is important to examine key-value store designs that reduce CPU overhead. However, current key-value stores are still designed mostly for hard disk drives (HDDs) that exhibit a large difference between sequential and random access(More)
We present the design and implementation of both an enhanced type of OSD device, the OSD+ device, and a metadata cluster based on it. OSD+s support data objects and directory objects. A directory object stores file names and attributes, and supports metadata--related operations. OSD+s profit the directory implementation and features of the underlying file(More)
Management of directories with millions of files, accessed by thousands of clients at the same time, is a problem recently identified in HPC environments. This paper introduces an OSD+-based technique to deal with those directories. We use directory objects in OSD+ devices for dynamically distributing a huge directory among several servers. Directory(More)
We present the design and implementation of both an enhanced new type of OSD device, the OSD+ device, and a metadata cluster based on it. The new OSD+ devices support data objects and directory objects. Unlike “data” objects, present in a traditional OSD, directory objects store file names and attributes, and support metadata-related operations. By using(More)
Current storage trends dictate placing fast storage devices in all servers and using them as a single distributed storage system. In this converged model where storage and compute resources co-exist in the same server, the role of the network is becoming more important: network overhead is becoming a main limitation to improving storage performance. In our(More)
The selection of the right I/O scheduler for a givenworkload can significantly improve the I/Operformance. However, this is not an easy task because several factors should be considered, and even the ‘‘best’’ scheduler can change over the time, specially if the workload’s characteristics change too. To address this problem, we present a Dynamic and(More)